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Publisher: John Wiley and Sons   (Total: 1597 journals)

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Showing 1 - 200 of 1597 Journals sorted alphabetically
Abacus     Hybrid Journal   (Followers: 13, SJR: 0.48, h-index: 22)
About Campus     Hybrid Journal   (Followers: 5)
Academic Emergency Medicine     Hybrid Journal   (Followers: 67, SJR: 1.385, h-index: 91)
Accounting & Finance     Hybrid Journal   (Followers: 49, SJR: 0.547, h-index: 30)
ACEP NOW     Free   (Followers: 1)
Acta Anaesthesiologica Scandinavica     Hybrid Journal   (Followers: 55, SJR: 1.02, h-index: 88)
Acta Archaeologica     Hybrid Journal   (Followers: 176, SJR: 0.101, h-index: 9)
Acta Geologica Sinica (English Edition)     Hybrid Journal   (Followers: 3, SJR: 0.552, h-index: 41)
Acta Neurologica Scandinavica     Hybrid Journal   (Followers: 5, SJR: 1.203, h-index: 74)
Acta Obstetricia et Gynecologica Scandinavica     Hybrid Journal   (Followers: 14, SJR: 1.197, h-index: 81)
Acta Ophthalmologica     Hybrid Journal   (Followers: 7, SJR: 0.112, h-index: 1)
Acta Paediatrica     Hybrid Journal   (Followers: 56, SJR: 0.794, h-index: 88)
Acta Physiologica     Hybrid Journal   (Followers: 6, SJR: 1.69, h-index: 88)
Acta Polymerica     Hybrid Journal   (Followers: 9)
Acta Psychiatrica Scandinavica     Hybrid Journal   (Followers: 37, SJR: 2.518, h-index: 113)
Acta Zoologica     Hybrid Journal   (Followers: 7, SJR: 0.459, h-index: 29)
Acute Medicine & Surgery     Hybrid Journal   (Followers: 5)
Addiction     Hybrid Journal   (Followers: 36, SJR: 2.086, h-index: 143)
Addiction Biology     Hybrid Journal   (Followers: 15, SJR: 2.091, h-index: 57)
Adultspan J.     Hybrid Journal   (SJR: 0.127, h-index: 4)
Advanced Energy Materials     Hybrid Journal   (Followers: 26, SJR: 6.411, h-index: 86)
Advanced Engineering Materials     Hybrid Journal   (Followers: 28, SJR: 0.81, h-index: 81)
Advanced Functional Materials     Hybrid Journal   (Followers: 51, SJR: 5.21, h-index: 203)
Advanced Healthcare Materials     Hybrid Journal   (Followers: 14, SJR: 0.232, h-index: 7)
Advanced Materials     Hybrid Journal   (Followers: 284, SJR: 9.021, h-index: 345)
Advanced Materials Interfaces     Hybrid Journal   (Followers: 6, SJR: 1.177, h-index: 10)
Advanced Optical Materials     Hybrid Journal   (Followers: 7, SJR: 2.488, h-index: 21)
Advanced Science     Open Access   (Followers: 5)
Advanced Synthesis & Catalysis     Hybrid Journal   (Followers: 18, SJR: 2.729, h-index: 121)
Advances in Polymer Technology     Hybrid Journal   (Followers: 14, SJR: 0.344, h-index: 31)
Africa Confidential     Hybrid Journal   (Followers: 21)
Africa Research Bulletin: Economic, Financial and Technical Series     Hybrid Journal   (Followers: 13)
Africa Research Bulletin: Political, Social and Cultural Series     Hybrid Journal   (Followers: 11)
African Development Review     Hybrid Journal   (Followers: 33, SJR: 0.275, h-index: 17)
African J. of Ecology     Hybrid Journal   (Followers: 16, SJR: 0.477, h-index: 39)
Aggressive Behavior     Hybrid Journal   (Followers: 17, SJR: 1.391, h-index: 66)
Aging Cell     Open Access   (Followers: 11, SJR: 4.374, h-index: 95)
Agribusiness : an Intl. J.     Hybrid Journal   (Followers: 3, SJR: 0.627, h-index: 14)
Agricultural and Forest Entomology     Hybrid Journal   (Followers: 16, SJR: 0.925, h-index: 43)
Agricultural Economics     Hybrid Journal   (Followers: 45, SJR: 1.099, h-index: 51)
AIChE J.     Hybrid Journal   (Followers: 32, SJR: 1.122, h-index: 120)
Alcoholism and Drug Abuse Weekly     Hybrid Journal   (Followers: 7)
Alcoholism Clinical and Experimental Research     Hybrid Journal   (Followers: 7, SJR: 1.416, h-index: 125)
Alimentary Pharmacology & Therapeutics     Hybrid Journal   (Followers: 34, SJR: 2.833, h-index: 138)
Alimentary Pharmacology & Therapeutics Symposium Series     Hybrid Journal   (Followers: 3)
Allergy     Hybrid Journal   (Followers: 50, SJR: 3.048, h-index: 129)
Alternatives to the High Cost of Litigation     Hybrid Journal   (Followers: 3)
American Anthropologist     Hybrid Journal   (Followers: 152, SJR: 0.951, h-index: 61)
American Business Law J.     Hybrid Journal   (Followers: 24, SJR: 0.205, h-index: 17)
American Ethnologist     Hybrid Journal   (Followers: 94, SJR: 2.325, h-index: 51)
American J. of Economics and Sociology     Hybrid Journal   (Followers: 30, SJR: 0.211, h-index: 26)
American J. of Hematology     Hybrid Journal   (Followers: 35, SJR: 1.761, h-index: 77)
American J. of Human Biology     Hybrid Journal   (Followers: 13, SJR: 1.018, h-index: 58)
American J. of Industrial Medicine     Hybrid Journal   (Followers: 16, SJR: 0.993, h-index: 85)
American J. of Medical Genetics Part A     Hybrid Journal   (Followers: 17, SJR: 1.115, h-index: 61)
American J. of Medical Genetics Part B: Neuropsychiatric Genetics     Hybrid Journal   (Followers: 4, SJR: 1.771, h-index: 107)
American J. of Medical Genetics Part C: Seminars in Medical Genetics     Partially Free   (Followers: 6, SJR: 2.315, h-index: 79)
American J. of Physical Anthropology     Hybrid Journal   (Followers: 38, SJR: 1.41, h-index: 88)
American J. of Political Science     Hybrid Journal   (Followers: 300, SJR: 5.101, h-index: 114)
American J. of Primatology     Hybrid Journal   (Followers: 14, SJR: 1.197, h-index: 63)
American J. of Reproductive Immunology     Hybrid Journal   (Followers: 4, SJR: 1.347, h-index: 75)
American J. of Transplantation     Hybrid Journal   (Followers: 19, SJR: 2.792, h-index: 140)
American J. on Addictions     Hybrid Journal   (Followers: 10, SJR: 0.843, h-index: 57)
Anaesthesia     Hybrid Journal   (Followers: 146, SJR: 1.404, h-index: 88)
Analyses of Social Issues and Public Policy     Hybrid Journal   (Followers: 10, SJR: 0.397, h-index: 18)
Analytic Philosophy     Hybrid Journal   (Followers: 20)
Anatomia, Histologia, Embryologia: J. of Veterinary Medicine Series C     Hybrid Journal   (Followers: 3, SJR: 0.295, h-index: 27)
Anatomical Sciences Education     Hybrid Journal   (Followers: 1, SJR: 0.633, h-index: 24)
Andrologia     Hybrid Journal   (Followers: 2, SJR: 0.528, h-index: 45)
Andrology     Hybrid Journal   (Followers: 2, SJR: 0.979, h-index: 14)
Angewandte Chemie     Hybrid Journal   (Followers: 175)
Angewandte Chemie Intl. Edition     Hybrid Journal   (Followers: 238, SJR: 6.229, h-index: 397)
Animal Conservation     Hybrid Journal   (Followers: 41, SJR: 1.576, h-index: 62)
Animal Genetics     Hybrid Journal   (Followers: 8, SJR: 0.957, h-index: 67)
Animal Science J.     Hybrid Journal   (Followers: 6, SJR: 0.569, h-index: 24)
Annalen der Physik     Hybrid Journal   (Followers: 5, SJR: 1.46, h-index: 40)
Annals of Anthropological Practice     Partially Free   (Followers: 2, SJR: 0.187, h-index: 5)
Annals of Applied Biology     Hybrid Journal   (Followers: 7, SJR: 0.816, h-index: 56)
Annals of Clinical and Translational Neurology     Open Access   (Followers: 1)
Annals of Gastroenterological Surgery     Open Access  
Annals of Human Genetics     Hybrid Journal   (Followers: 9, SJR: 1.191, h-index: 67)
Annals of Neurology     Hybrid Journal   (Followers: 49, SJR: 5.584, h-index: 241)
Annals of Noninvasive Electrocardiology     Hybrid Journal   (Followers: 1, SJR: 0.531, h-index: 38)
Annals of Public and Cooperative Economics     Hybrid Journal   (Followers: 8, SJR: 0.336, h-index: 23)
Annals of the New York Academy of Sciences     Hybrid Journal   (Followers: 5, SJR: 2.389, h-index: 189)
Annual Bulletin of Historical Literature     Hybrid Journal   (Followers: 12)
Annual Review of Information Science and Technology     Hybrid Journal   (Followers: 14)
Anthropology & Education Quarterly     Hybrid Journal   (Followers: 26, SJR: 0.72, h-index: 31)
Anthropology & Humanism     Hybrid Journal   (Followers: 18, SJR: 0.137, h-index: 3)
Anthropology News     Hybrid Journal   (Followers: 15)
Anthropology of Consciousness     Hybrid Journal   (Followers: 11, SJR: 0.172, h-index: 5)
Anthropology of Work Review     Hybrid Journal   (Followers: 11, SJR: 0.256, h-index: 5)
Anthropology Today     Hybrid Journal   (Followers: 94, SJR: 0.545, h-index: 15)
Antipode     Hybrid Journal   (Followers: 54, SJR: 2.212, h-index: 69)
Anz J. of Surgery     Hybrid Journal   (Followers: 8, SJR: 0.432, h-index: 59)
Anzeiger für Schädlingskunde     Hybrid Journal   (Followers: 1)
Apmis     Hybrid Journal   (Followers: 1, SJR: 0.855, h-index: 73)
Applied Cognitive Psychology     Hybrid Journal   (Followers: 74, SJR: 0.754, h-index: 69)
Applied Organometallic Chemistry     Hybrid Journal   (Followers: 7, SJR: 0.632, h-index: 58)
Applied Psychology     Hybrid Journal   (Followers: 170, SJR: 1.023, h-index: 64)
Applied Psychology: Health and Well-Being     Hybrid Journal   (Followers: 53, SJR: 0.868, h-index: 13)
Applied Stochastic Models in Business and Industry     Hybrid Journal   (Followers: 5, SJR: 0.613, h-index: 24)
Aquaculture Nutrition     Hybrid Journal   (Followers: 12, SJR: 1.025, h-index: 55)
Aquaculture Research     Hybrid Journal   (Followers: 31, SJR: 0.807, h-index: 60)
Aquatic Conservation Marine and Freshwater Ecosystems     Hybrid Journal   (Followers: 36, SJR: 1.047, h-index: 57)
Arabian Archaeology and Epigraphy     Hybrid Journal   (Followers: 12, SJR: 0.453, h-index: 11)
Archaeological Prospection     Hybrid Journal   (Followers: 12, SJR: 0.922, h-index: 21)
Archaeology in Oceania     Hybrid Journal   (Followers: 13, SJR: 0.745, h-index: 18)
Archaeometry     Hybrid Journal   (Followers: 31, SJR: 0.809, h-index: 48)
Archeological Papers of The American Anthropological Association     Hybrid Journal   (Followers: 15, SJR: 0.156, h-index: 2)
Architectural Design     Hybrid Journal   (Followers: 29, SJR: 0.261, h-index: 9)
Archiv der Pharmazie     Hybrid Journal   (Followers: 3, SJR: 0.628, h-index: 43)
Archives of Drug Information     Hybrid Journal   (Followers: 5)
Archives of Insect Biochemistry and Physiology     Hybrid Journal   (SJR: 0.768, h-index: 54)
Area     Hybrid Journal   (Followers: 13, SJR: 0.938, h-index: 57)
Art History     Hybrid Journal   (Followers: 273, SJR: 0.153, h-index: 13)
Arthritis & Rheumatology     Hybrid Journal   (Followers: 56, SJR: 1.984, h-index: 20)
Arthritis Care & Research     Hybrid Journal   (Followers: 29, SJR: 2.256, h-index: 114)
Artificial Organs     Hybrid Journal   (Followers: 1, SJR: 0.872, h-index: 60)
ASHE Higher Education Reports     Hybrid Journal   (Followers: 16)
Asia & the Pacific Policy Studies     Open Access   (Followers: 17)
Asia Pacific J. of Human Resources     Hybrid Journal   (Followers: 329, SJR: 0.494, h-index: 19)
Asia Pacific Viewpoint     Hybrid Journal   (Followers: 1, SJR: 0.616, h-index: 26)
Asia-Pacific J. of Chemical Engineering     Hybrid Journal   (Followers: 8, SJR: 0.345, h-index: 20)
Asia-pacific J. of Clinical Oncology     Hybrid Journal   (Followers: 6, SJR: 0.554, h-index: 14)
Asia-Pacific J. of Financial Studies     Hybrid Journal   (SJR: 0.241, h-index: 7)
Asia-Pacific Psychiatry     Hybrid Journal   (Followers: 4, SJR: 0.377, h-index: 7)
Asian Economic J.     Hybrid Journal   (Followers: 8, SJR: 0.234, h-index: 21)
Asian Economic Policy Review     Hybrid Journal   (Followers: 4, SJR: 0.196, h-index: 12)
Asian J. of Control     Hybrid Journal   (SJR: 0.862, h-index: 34)
Asian J. of Endoscopic Surgery     Hybrid Journal   (Followers: 1, SJR: 0.394, h-index: 7)
Asian J. of Organic Chemistry     Hybrid Journal   (Followers: 6, SJR: 1.443, h-index: 19)
Asian J. of Social Psychology     Hybrid Journal   (Followers: 6, SJR: 0.665, h-index: 37)
Asian Politics and Policy     Hybrid Journal   (Followers: 12, SJR: 0.207, h-index: 7)
Asian Social Work and Policy Review     Hybrid Journal   (Followers: 5, SJR: 0.318, h-index: 5)
Asian-pacific Economic Literature     Hybrid Journal   (Followers: 5, SJR: 0.168, h-index: 15)
Assessment Update     Hybrid Journal   (Followers: 4)
Astronomische Nachrichten     Hybrid Journal   (Followers: 3, SJR: 0.701, h-index: 40)
Atmospheric Science Letters     Open Access   (Followers: 29, SJR: 1.332, h-index: 27)
Austral Ecology     Hybrid Journal   (Followers: 15, SJR: 1.095, h-index: 66)
Austral Entomology     Hybrid Journal   (Followers: 9, SJR: 0.524, h-index: 28)
Australasian J. of Dermatology     Hybrid Journal   (Followers: 8, SJR: 0.714, h-index: 40)
Australasian J. On Ageing     Hybrid Journal   (Followers: 6, SJR: 0.39, h-index: 22)
Australian & New Zealand J. of Statistics     Hybrid Journal   (Followers: 14, SJR: 0.275, h-index: 28)
Australian Accounting Review     Hybrid Journal   (Followers: 3, SJR: 0.709, h-index: 14)
Australian and New Zealand J. of Family Therapy (ANZJFT)     Hybrid Journal   (Followers: 3, SJR: 0.382, h-index: 12)
Australian and New Zealand J. of Obstetrics and Gynaecology     Hybrid Journal   (Followers: 46, SJR: 0.814, h-index: 49)
Australian and New Zealand J. of Public Health     Hybrid Journal   (Followers: 13, SJR: 0.82, h-index: 62)
Australian Dental J.     Hybrid Journal   (Followers: 6, SJR: 0.482, h-index: 46)
Australian Economic History Review     Hybrid Journal   (Followers: 6, SJR: 0.171, h-index: 12)
Australian Economic Papers     Hybrid Journal   (Followers: 31, SJR: 0.23, h-index: 9)
Australian Economic Review     Hybrid Journal   (Followers: 6, SJR: 0.357, h-index: 21)
Australian Endodontic J.     Hybrid Journal   (Followers: 3, SJR: 0.513, h-index: 24)
Australian J. of Agricultural and Resource Economics     Hybrid Journal   (Followers: 3, SJR: 0.765, h-index: 36)
Australian J. of Grape and Wine Research     Hybrid Journal   (Followers: 5, SJR: 0.879, h-index: 56)
Australian J. of Politics & History     Hybrid Journal   (Followers: 15, SJR: 0.203, h-index: 14)
Australian J. of Psychology     Hybrid Journal   (Followers: 18, SJR: 0.384, h-index: 30)
Australian J. of Public Administration     Hybrid Journal   (Followers: 443, SJR: 0.418, h-index: 29)
Australian J. of Rural Health     Hybrid Journal   (Followers: 6, SJR: 0.43, h-index: 34)
Australian Occupational Therapy J.     Hybrid Journal   (Followers: 75, SJR: 0.59, h-index: 29)
Australian Psychologist     Hybrid Journal   (Followers: 11, SJR: 0.331, h-index: 31)
Australian Veterinary J.     Hybrid Journal   (Followers: 23, SJR: 0.459, h-index: 45)
Autism Research     Hybrid Journal   (Followers: 38, SJR: 2.126, h-index: 39)
Autonomic & Autacoid Pharmacology     Hybrid Journal   (SJR: 0.371, h-index: 29)
Banks in Insurance Report     Hybrid Journal   (Followers: 1)
Basic & Clinical Pharmacology & Toxicology     Hybrid Journal   (Followers: 11, SJR: 0.539, h-index: 70)
Basic and Applied Pathology     Open Access   (Followers: 2, SJR: 0.113, h-index: 4)
Basin Research     Hybrid Journal   (Followers: 5, SJR: 1.54, h-index: 60)
Bauphysik     Hybrid Journal   (Followers: 2, SJR: 0.194, h-index: 5)
Bauregelliste A, Bauregelliste B Und Liste C     Hybrid Journal  
Bautechnik     Hybrid Journal   (Followers: 1, SJR: 0.321, h-index: 11)
Behavioral Interventions     Hybrid Journal   (Followers: 10, SJR: 0.297, h-index: 23)
Behavioral Sciences & the Law     Hybrid Journal   (Followers: 23, SJR: 0.736, h-index: 57)
Berichte Zur Wissenschaftsgeschichte     Hybrid Journal   (Followers: 10, SJR: 0.11, h-index: 5)
Beton- und Stahlbetonbau     Hybrid Journal   (Followers: 2, SJR: 0.493, h-index: 14)
Biochemistry and Molecular Biology Education     Hybrid Journal   (Followers: 6, SJR: 0.311, h-index: 26)
Bioelectromagnetics     Hybrid Journal   (Followers: 1, SJR: 0.568, h-index: 64)
Bioengineering & Translational Medicine     Open Access  
BioEssays     Hybrid Journal   (Followers: 10, SJR: 3.104, h-index: 155)
Bioethics     Hybrid Journal   (Followers: 14, SJR: 0.686, h-index: 39)
Biofuels, Bioproducts and Biorefining     Hybrid Journal   (Followers: 1, SJR: 1.725, h-index: 56)
Biological J. of the Linnean Society     Hybrid Journal   (Followers: 18, SJR: 1.172, h-index: 90)
Biological Reviews     Hybrid Journal   (Followers: 5, SJR: 6.469, h-index: 114)
Biologie in Unserer Zeit (Biuz)     Hybrid Journal   (Followers: 41, SJR: 0.12, h-index: 1)
Biology of the Cell     Full-text available via subscription   (Followers: 9, SJR: 1.812, h-index: 69)
Biomedical Chromatography     Hybrid Journal   (Followers: 7, SJR: 0.572, h-index: 49)
Biometrical J.     Hybrid Journal   (Followers: 5, SJR: 0.784, h-index: 44)
Biometrics     Hybrid Journal   (Followers: 37, SJR: 1.906, h-index: 96)
Biopharmaceutics and Drug Disposition     Hybrid Journal   (Followers: 10, SJR: 0.715, h-index: 44)
Biopolymers     Hybrid Journal   (Followers: 18, SJR: 1.199, h-index: 104)
Biotechnology and Applied Biochemistry     Hybrid Journal   (Followers: 44, SJR: 0.415, h-index: 55)
Biotechnology and Bioengineering     Hybrid Journal   (Followers: 161, SJR: 1.633, h-index: 146)
Biotechnology J.     Hybrid Journal   (Followers: 15, SJR: 1.185, h-index: 51)
Biotechnology Progress     Hybrid Journal   (Followers: 39, SJR: 0.736, h-index: 101)
Biotropica     Hybrid Journal   (Followers: 20, SJR: 1.374, h-index: 71)
Bipolar Disorders     Hybrid Journal   (Followers: 9, SJR: 2.592, h-index: 100)
Birth     Hybrid Journal   (Followers: 38, SJR: 0.763, h-index: 64)
Birth Defects Research Part A : Clinical and Molecular Teratology     Hybrid Journal   (Followers: 2, SJR: 0.727, h-index: 77)
Birth Defects Research Part B: Developmental and Reproductive Toxicology     Hybrid Journal   (Followers: 8, SJR: 0.468, h-index: 47)
Birth Defects Research Part C : Embryo Today : Reviews     Hybrid Journal   (SJR: 1.513, h-index: 55)

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Journal Cover Advanced Energy Materials
  [SJR: 6.411]   [H-I: 86]   [26 followers]  Follow
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
   ISSN (Online) 1614-6840
   Published by John Wiley and Sons Homepage  [1597 journals]
  • Ion Transport Nanotube Assembled with Vertically Aligned Metallic MoS2 for
           High Rate Lithium-Ion Batteries
    • Authors: Yucong Jiao; Alolika Mukhopadhyay, Yi Ma, Lei Yang, Ahmed M. Hafez, Hongli Zhu
      Abstract: Metallic phase molybdenum disulfide (MoS2) is well known for orders of magnitude higher conductivity than 2H semiconducting phase MoS2. Herein, for the first time, the authors design and fabricate a novel porous nanotube assembled with vertically aligned metallic MoS2 nanosheets by using the scalable solvothermal method. This metallic nanotube has the following advantages: (i) intrinsic high electrical conductivity that promotes the rate performance of battery and eliminates the using of conductive additive; (ii) hierarchical, hollow, porous, and aligned structure that assists the electrolyte transportation and diffusion; (iii) tubular structure that avoids restacking of 2D nanosheets, and therefore maintains the electrochemistry cycling stability; and (iv) a shortened ion diffusion path, that improves the rate performance. This 1D metallic MoS2 nanotube is demonstrated to be a promising anode material for lithium-ion batteries. The unique structure delivers an excellent reversible capacity of 1100 mA h g−1 under a current density of 5 A g−1 after 350 cycles, and an outstanding rate performance of 589 mA h g−1 at a current density of 20 A g−1. Furthermore, attributed to the material's metallic properties, the electrode comprising 100% pure material without any additive provides an ideal system for the fundamental electrochemical study of metallic MoS2. This study first reveals the characteristic anodic peak at 1.5 V in cyclic voltammetry of metallic MoS2. This research sheds light on the fabrication of metallic 1D, 2D, or even 3D structures with 2D nanosheets as building blocks for various applications.The reported metallic and porous nanotube is first assembled with vertically aligned multi-layers metallic MoS2 nanosheets, which can stabilize the metallic phase for more than 120 days. This porous and metallic nanotube with excellent intrinsic electronic conductivity, not only benefits the electron and ion transportation, but also exhibits distinguished stability. The obtained conductive additive free electrode leads to an exceptional electrochemical performance as a lithium-ion battery anode and retains a stable metallic phase for long cycling.
      PubDate: 2018-01-12T03:44:23.380767-05:
      DOI: 10.1002/aenm.201702779
  • The Synergistic Effect of Cation and Anion of an Ionic Liquid Additive for
           Lithium Metal Anodes
    • Authors: Dong-Joo Yoo; Ki Jae Kim, Jang Wook Choi
      Abstract: Lithium metal anodes are steadily gaining more attention, as their superior specific capacities and low redox voltage can significantly increase the energy density of rechargeable batteries far beyond those of current Li-ion batteries. Nonetheless, the relevant technology is still in a premature research stage mainly due to the uncontrolled growth of Li dendrites that ceaselessly cause unwanted side reactions with electrolyte. In order to circumvent this shortcoming, herein, an ionic liquid additive, namely, 1-dodecyl-1-methylpyrrolidinium (Pyr1(12)+) bis(fluorosulfonyl)imide (FSI−), for conventional electrolyte solutions is reported. The Pyr1(12)+ cation with a long aliphatic chain mitigates dendrite growth via the combined effects of electrostatic shielding and lithiophobicity, whereas the FSI− anion can induce the formation of rigid solid–electrolyte interphase layers. The synergy between the cation and anion significantly improves cycling performance in asymmetric and symmetric control cells and a full cell paired with an LiFePO4 cathode. The present study provides a useful insight into the molecular engineering of electrolyte components by manipulating the charge and structures of the involved molecules.An ionic liquid additive of 1-dodecyl-1-methylpyrrolidinium (Pyr1(12)+) bis(fluorosulfonyl)imide (FSI-) is reported for stable cycling of Li metal anodes. The Pyr1(12)+ cation with a long aliphatic chain engages an electrostatic shielding and lithiophobic effect, whereas the FSI- anion induces the formation of rigid solid–electrolyte interphase layers. The synergy between both ions suppresses dendrite growth and improves electrochemical performance significantly.
      PubDate: 2018-01-12T03:43:53.586203-05:
      DOI: 10.1002/aenm.201702744
  • Metal–Organic Framework Templated Pd@PdO–Co3O4 Nanocubes as an
           Efficient Bifunctional Oxygen Electrocatalyst
    • Authors: Hong-Chao Li; Ying-Jie Zhang, Xiao Hu, Wu-Jun Liu, Jie-Jie Chen, Han-Qing Yu
      Abstract: The development of high-efficiency bifunctional electrocatalyst for oxygen reduction and evolution reactions (ORR/OER) is critical for rechargeable metal–air batteries, a typical electrochemical energy storage and conversion technology. This work reports a general approach for the synthesis of Pd@PdO–Co3O4 nanocubes using the zeolite-type metal–organic framework (MOF) as a template. The as-synthesized materials exhibit a high electrocatalytic activity toward OER and ORR, which is comparable to those of commercial RuO2 and Pt/C electrocatalysts, while its cycle performance and stability are much higher than those of commercial RuO2 and Pt/C electrocatalysts. Various physicochemical characterizations and density functional theory calculations indicate that the favorable electrochemical performance of the Pd@PdO–Co3O4 nanocubes is mainly attributed to the synergistic effect between PdO and the robust hollow structure composed of interconnected crystalline Co3O4 nanocubes. This work establishes an efficient approach for the controlled design and synthesis of MOF-templated hybrid nanomaterials, and provides a great potential for developing high-performance electrocatalysts in energy storage and conversion.This work reports a general approach to synthesize Pd@PdO-Co3O4 nanocubes using the zeolite-type metal–organic framework (MOF) as a template. The as-synthesized material exhibits a high electrocatalytic activity toward Oxygen evolution and reduction reactions (OER and ORR). Synergistic effects between PdO and the robust hollow structure crystalline Co3O4 nanocubes are the main contributions to the catalyst's excellent performance.
      PubDate: 2018-01-12T03:43:04.615362-05:
      DOI: 10.1002/aenm.201702734
  • Blood-Capillary-Inspired, Free-Standing, Flexible, and Low-Cost
           Super-Hydrophobic N-CNTs@SS Cathodes for High-Capacity, High-Rate, and
           Stable Li-Air Batteries
    • Authors: Xiao-Yang Yang; Ji-Jing Xu, Zhi-Wen Chang, Di Bao, Yan-Bin Yin, Tong Liu, Jun-Min Yan, Da-Peng Liu, Yu Zhang, Xin-Bo Zhang
      Abstract: With the rising demand for flexible and wearable electronic devices, flexible power sources with high energy densities are required to provide a sustainable energy supply. Theoretically, rechargeable, flexible Li-O2/air batteries can provide extremely high specific energy densities; however, the high costs, complex synthetic methods, and inferior mechanical properties of the available flexible cathodes severely limit their practical applications. Herein, inspired by the structure of human blood capillary tissue, this study demonstrates for the first time the in situ growth of interpenetrative hierarchical N-doped carbon nanotubes on the surface of stainless-steel mesh (N-CNTs@SS) for the fabrication of a self-supporting, flexible electrode with excellent physicochemical properties via a facile and scalable one-step strategy. Benefitting from the synergistic effects of the high electronic conductivity and stable 3D interconnected conductive network structure, the Li-O2 batteries obtained with the N-CNTs@SS cathode exhibit superior electrochemical performance, including a high specific capacity (9299 mA h g−1 at 500 mA g−1), an excellent rate capability, and an exceptional cycle stability (up to 232 cycles). Furthermore, as-fabricated flexible Li-air batteries containing the as-prepared flexible super-hydrophobic cathode show excellent mechanical properties, stable electrochemical performance, and superior H2O resistibility, which enhance their potential to power flexible and wearable electronic devices.Inspired by blood capillary tissue, a self-standing, flexible N-CNTs@SS Li-O2 battery cathode with an interpenetrative structure is fabricated via a facile and scalable one-step strategy. The flexible Li-O2 batteries with N-CNTs@SS exhibit excellent mechanical properties, stable electrochemical performance, and superior H2O resistibility.
      PubDate: 2018-01-11T12:30:02.921909-05:
      DOI: 10.1002/aenm.201702242
  • Highly Efficient Ambient Temperature CO2 Photomethanation Catalyzed by
           Nanostructured RuO2 on Silicon Photonic Crystal Support
    • Authors: Abdinoor A. Jelle; Kulbir K. Ghuman, Paul G. O'Brien, Mohamad Hmadeh, Amit Sandhel, Doug D. Perovic, Chandra Veer Singh, Charles A. Mims, Geoffrey A. Ozin
      Abstract: Sunlight-driven catalytic hydrogenation of CO2 is an important reaction that generates useful chemicals and fuels and if operated at industrial scales can decrease greenhouse gas CO2 emissions into the atmosphere. In this work, the photomethanation of CO2 over highly dispersed nanostructured RuO2 catalysts on 3D silicon photonic crystal supports, achieving impressive conversion rates as high as 4.4 mmol gcat−1 h−1 at ambient temperatures under high-intensity solar simulated irradiation, is reported. This performance is an order of magnitude greater than photomethanation rates achieved over control samples made of nanostructured RuO2 on silicon wafers. The high absorption and unique light-harvesting properties of the silicon photonic crystal across the entire solar spectral wavelength range coupled with its large surface area are proposed to be responsible for the high methanation rates of the RuO2 photocatalyst. A density functional theory study on the reaction of CO2 with H2 revealed that H2 splits on the surface of the RuO2 to form hydroxyl groups that participate in the overall photomethanation process.A nanocrystalline RuO2 supported 3D silicon photonic crystal is shown to be a highly active photomethanation catalyst. The catalyst produces CH4 at a remarkable rate of 4.4 mmol gcat−1 h−1 at ambient temperatures. This exceptional photomethanation rate is due to the large surface area coupled with the unique light-harvesting properties of the photonic crystal support.
      PubDate: 2018-01-11T12:29:29.994943-05:
      DOI: 10.1002/aenm.201702277
  • Facile Synthesis of Crumpled Nitrogen-Doped MXene Nanosheets as a New
           Sulfur Host for Lithium–Sulfur Batteries
    • Authors: Weizhai Bao; Lin Liu, Chengyin Wang, Sinho Choi, Dan Wang, Guoxiu Wang
      Abstract: Crumpled nitrogen-doped MXene nanosheets with strong physical and chemical coadsorption of polysulfides are synthesized by a novel one-step approach and then utilized as a new sulfur host for lithium–sulfur batteries. The nitrogen-doping strategy enables introduction of heteroatoms into MXene nanosheets and simultaneously induces a well-defined porous structure, high surface area, and large pore volume. The as-prepared nitrogen-doped MXene nanosheets have a strong capability of physical and chemical dual-adsorption for polysulfides and achieve a high areal sulfur loading of 5.1 mg cm–2. Lithium–sulfur batteries, based on crumpled nitrogen-doped MXene nanosheets/sulfur composites, demonstrate outstanding electrochemical performances, including a high reversible capacity (1144 mA h g–1 at 0.2C rate) and an extended cycling stability (610 mA h g–1 at 2C after 1000 cycles).A novel strategy is applied to dope nitrogen into MXene frameworks. The resultant nitrogen-doped MXene nanosheets have a well-defined crumpled structure, a high surface area, and large pore volume. The nitrogen-doped crumpled MXene nanosheets demonstrate strong physical and chemical coadsorption of polysulfides. When used as cathode hosts, lithium–sulfur batteries exhibit outstanding electrochemical performance.
      PubDate: 2018-01-11T12:28:59.124146-05:
      DOI: 10.1002/aenm.201702485
  • A Chemical Approach to Raise Cell Voltage and Suppress Phase Transition in
           O3 Sodium Layered Oxide Electrodes
    • Authors: Mariyappan Sathiya; Quentin Jacquet, Marie-Liesse Doublet, Olesia M. Karakulina, Joke Hadermann, Jean-Marie Tarascon
      Abstract: Sodium ion batteries (NIBs) are one of the versatile technologies for low-cost rechargeable batteries. O3-type layered sodium transition metal oxides (NaMO2, M = transition metal ions) are one of the most promising positive electrode materials considering their capacity. However, the use of O3 phases is limited due to their low redox voltage and associated multiple phase transitions which are detrimental for long cycling. Herein, a simple strategy is proposed to successfully combat these issues. It consists of the introduction of a larger, nontransition metal ion Sn4+ in NaMO2 to prepare a series of NaNi0.5Mn0.5−ySnyO2 (y = 0–0.5) compositions with attractive electrochemical performances, namely for y = 0.5, which shows a single-phase transition from O3 P3 at the very end of the oxidation process. Na-ion NaNi0.5Sn0.5O2/C coin cells are shown to deliver an average cell voltage of 3.1 V with an excellent capacity retention as compared to an average stepwise voltage of ≈2.8 V and limited capacity retention for the pure NaNi0.5Mn0.5O2 phase. This study potentially shows the way to manipulate the O3 NaMO2 for facilitating their practical use in NIBs.A cobalt-free sodium layered oxide electrode material O3 NaNi0.5Sn0.5O2 that shows long-term cycling performance due to suppressed phase transitions and high voltage (3.2 V) owing to the increased ionicity of the NiO bond via Sn substitution.
      PubDate: 2018-01-11T12:28:26.506385-05:
      DOI: 10.1002/aenm.201702599
  • Tailored Electron Transfer Pathways in Aucore/Ptshell–Graphene
           Nanocatalysts for Fuel Cells
    • Authors: Nedjeljko Seselj; Christian Engelbrekt, Yi Ding, Hans Aage Hjuler, Jens Ulstrup, Jingdong Zhang
      Abstract: Aucore/Ptshell–graphene catalysts (G-Cys-Au@Pt) are prepared through chemical and surface chemical reactions. Au–Pt core–shell nanoparticles (Au@Pt NPs) covalently immobilized on graphene (G) are efficient electrocatalysts in low-temperature polymer electrolyte membrane fuel cells. The 9.5 ± 2 nm Au@Pt NPs with atomically thin Pt shells are attached on graphene via l-cysteine (Cys), which serves as linkers controlling NP loading and dispersion, enhancing the Au@Pt NP stability, and facilitating interfacial electron transfer. The increased activity of G-Cys-Au@Pt, compared to non-chemically immobilized G-Au@Pt and commercial platinum NPs catalyst (C-Pt), is a result of (1) the tailored electron transfer pathways of covalent bonds integrating Au@Pt NPs into the graphene framework, and (2) synergetic electronic effects of atomically thin Pt shells on Au cores. Enhanced electrocatalytic oxidation of formic acid, methanol, and ethanol is observed as higher specific currents and increased stability of G-Cys-Au@Pt compared to G-Au@Pt and C–Pt. Oxygen reduction on G-Cys-Au@Pt occurs at 25 mV lower potential and 43 A gPt−1 higher current (at 0.9 V vs reversible hydrogen electrode) than for C–Pt. Functional tests in direct fomic acid, methanol and ethanol fuel cells exhibit 95%, 53%, and 107% increased power densities for G-Cys-Au@Pt over C–Pt, respectively.Au nanoparticles with atomically thin Pt shells are covalently immobilized on graphene via cysteine anchors for electrocatalytic fuel conversion. Demonstrated high performance in fuel cells is due to efficient electron transfer (blue), fuel oxidation (green), and dioxygen reduction (red).
      PubDate: 2018-01-11T12:27:48.633343-05:
      DOI: 10.1002/aenm.201702609
  • Topotactic Engineering of Ultrathin 2D Nonlayered Nickel Selenides for
           Full Water Electrolysis
    • Authors: Hao Wu; Xin Lu, Gengfeng Zheng, Ghim Wei Ho
      Abstract: Fabrication of ultrathin 2D nonlayered nanomaterials remains challenging, yet significant due to the new promises in electrochemical functionalities. However, current strategies are largely restricted to intrinsically layered materials. Herein, a combinatorial self-regulating acid etching and topotactic transformation strategy is developed to unprecedentedly prepare vertically stacked ultrathin 2D nonlayered nickel selenide nanosheets. Due to the inhibited hydrolyzation under acidic conditions, the self-regulating acid etching results in ultrathin layered nickel hydroxides (two layers). The ultrathin structure allows limited epitaxial extension during selenization, i.e., the nondestructive topotactic transformation, enabling facile artificial engineering of hydroxide foundation frameworks into ultrathin nonlayered selenides. Consequently, the exquisite nonlayered nickel selenide affords high turnover frequencies, electrochemical surface areas, exchange current densities, and low Tafel slopes, as well as facilitating charge transfer toward both oxygen and hydrogen evolution reactions. Thus, the kinetically favorable bifunctional electrocatalyst delivers advanced and robust overall water splitting activities in alkaline intermediates. The integrated methodology may open up a new pathway for designing other highly active 2D nonlayered electrocatalysts.Ultrathin 2D nonlayered NiSe nanosheets with a thickness of 1.25 nm are synthesized via a nondestructive topotactic selenization from their unconventional acid-etched ultrathin layered Ni(OH)2 counterparts. The ultrathin character of the nanosheets is responsible for the intact selenization transformation, leading to advanced bifunctional oxygen evolution reaction and hydrogen evolution reaction catalytic activities in alkaline intermediates.
      PubDate: 2018-01-11T12:27:18.100461-05:
      DOI: 10.1002/aenm.201702704
  • A Stable Graphitic, Nanocarbon-Encapsulated, Cobalt-Rich Core–Shell
           Electrocatalyst as an Oxygen Electrode in a Water Electrolyzer
    • Authors: Arumugam Sivanantham; Pandian Ganesan, Luis Estevez, B. Peter McGrail, Radha Kishan Motkuri, Sangaraju Shanmugam
      Abstract: The oxygen electrode plays a vital role in the successful commercialization of renewable energy technologies, such as fuel cells and water electrolyzers. In this study, the Prussian blue analogue-derived nitrogen-doped nanocarbon (NC) layer-trapped, cobalt-rich, core–shell nanostructured electrocatalysts (core–shell Co@NC) are reported. The electrode exhibits an improved oxygen evolution activity and stability compared to that of the commercial noble electrodes. The core–shell Co@NC-loaded nickel foam exhibits a lower overpotential of 330 mV than that of IrO2 on nickel foam at 10 mA cm−2 and has a durability of over 400 h. The commercial Pt/C cathode-assisted, core–shell Co@NC–anode water electrolyzer delivers 10 mA cm−2 at a cell voltage of 1.59 V, which is 70 mV lower than that of the IrO2–anode water electrolyzer. Over the long-term chronopotentiometry durability testing, the IrO2–anode water electrolyzer shows a cell voltage loss of 230 mV (14%) at 95 h, but the loss of the core–shell Co@NC–anode electrolyzer is only 60 mV (4%) even after 350 h cell-operation. The findings indicate that the Prussian blue analogue is a class of inorganic nanoporous materials that can be used to derive metal-rich, core–shell electrocatalysts with enriched active centers.Prussian blue analogue-derived porous nanocarbon-encapsulated cobalt metal-rich core–shell electrocatalysts show improved oxygen evolution activity and ultrastability compared to the state-of-the-art catalyst in alkaline water electrolyzer, due to the existence of the coordinatively unsaturated active centers. Porous and thin carbon layers enhance the active site–electrolyte interface and suitable electron pathways during the water electrolysis.
      PubDate: 2018-01-11T12:26:32.004726-05:
      DOI: 10.1002/aenm.201702838
  • Material Discovery and Design Principles for Stable, High Activity
           Perovskite Cathodes for Solid Oxide Fuel Cells
    • Authors: Ryan Jacobs; Tam Mayeshiba, John Booske, Dane Morgan
      Abstract: Critical to the development of improved solid oxide fuel cell (SOFC) technology are novel compounds with high oxygen reduction reaction (ORR) catalytic activity and robust stability under cathode operating conditions. Approximately 2145 distinct perovskite compositions are screened for potential use as high activity, stable SOFC cathodes, and it is verified that the screening methodology qualitatively reproduces the experimental activity, stability, and conduction properties of well-studied cathode materials. The calculated oxygen p-band center is used as a first principle-based descriptor of the surface exchange coefficient (k*), which in turn correlates with cathode ORR activity. Convex hull analysis is used under operating conditions in the presence of oxygen, hydrogen, and water vapor to determine thermodynamic stability. This search has yielded 52 potential cathode materials with good predicted stability in typical SOFC operating conditions and predicted k* on par with leading ORR perovskite catalysts. The established trends in predicted k* and stability are used to suggest methods of improving the performance of known promising compounds. The material design strategies and new materials discovered in the computational search help enable the development of high activity, stable compounds for use in future solid oxide fuel cells and related applications.Materials with high oxygen reduction reaction (ORR) activity are crucial for future solid oxide fuel cell (SOFC) technology. This work uses a high-throughput computational materials design to screen a large perovskite composition space for stable, highly activity materials. Design principles to realize stable, highly active compounds and several examples of new materials with predicted performance exceeding current commercial materials are provided.
      PubDate: 2018-01-11T12:25:46.83595-05:0
      DOI: 10.1002/aenm.201702708
  • Alkyl Chain Regiochemistry of Benzotriazole-Based Donor Polymers
           Influencing Morphology and Performances of Non-Fullerene Organic Solar
    • Authors: Shangshang Chen; Lin Zhang, Chao Ma, Dong Meng, Jianquan Zhang, Guangye Zhang, Zhengke Li, Philip C. Y. Chow, Wei Ma, Zhaohui Wang, Kam Sing Wong, Harald Ade, He Yan
      Abstract: The effects of alkyl chain regiochemistry on the properties of donor polymers and performances of non-fullerene organic solar cells are investigated. Two donor polymers (PfBTAZ and PfBTAZS) are compared that have nearly identical chemical structures except for the regiochemistry of alkyl chains. The optical properties and crystallinity of two polymers are nearly identical yet the PfBTAZ:O-IDTBR blend exhibits nearly double domain size compared to the blend based on PfBTAZS:O-IDTBR. To reveal the origins of the very different domain size of two blends, the morphology of neat polymer films is characterized, and it is found that PfBTAZ tends to aggregate into much larger polymer fibers without the presence of O-IDTBR. This indicates that it is not the polymer:O-IDTBR interactions but the intrinsic aggregation properties of two polymers that determine the morphology features of neat and blend films. The stronger aggregation tendency of PfBTAZ could be explained by its more co-planar geometry of the polymer backbone arising from the different alkyl chain regiochemistry. Combined with the similar trend observed in another set of donor polymers (PTFB-P and PTFB-PS), the results provide an important understanding of the structure–property relationships that could guide the development of donor polymers for non-fullerene organic solar cells.The effects of alkyl chain regiochemistry on the properties of donor polymers and the performance of non-fullerene organic solar cells are investigated. It is found that the alkyl chain regiochemistry has great impacts on the morphology features of the neat and blend films, and the PfBTAZS:O-IDTBR-based cells with small domain size can achieve a high efficiency of 10.4%.
      PubDate: 2018-01-10T04:44:50.051329-05:
      DOI: 10.1002/aenm.201702427
  • A Practicable Li/Na-Ion Hybrid Full Battery Assembled by a High-Voltage
           Cathode and Commercial Graphite Anode: Superior Energy Storage Performance
           and Working Mechanism
    • Authors: Jin-Zhi Guo; Yang Yang, Dao-Sheng Liu, Xing-Long Wu, Bao-Hua Hou, Wei-Lin Pang, Ke-Cheng Huang, Jing-Ping Zhang, Zhong-Min Su
      Abstract: With the rapidly growing demand for low-cost and safe energy storage, the advanced battery concepts have triggered strong interests beyond the state-of-the-art Li-ion batteries (LIBs). Herein, a novel hybrid Li/Na-ion full battery (HLNIB) composed of the high-energy and lithium-free Na3V2(PO4)2O2F (NVPOF) cathode and commercial graphite anode mesophase carbon micro beads is for the first time designed. The assembled HLNIBs exhibit two high working voltage at about 4.05 and 3.69 V with a specific capacity of 112.7 mA h g−1. Its energy density can reach up to 328 W h kg−1 calculated from the total mass of both cathode and anode materials. Moreover, the HLNIBs show outstanding high-rate capability, long-term cycle life, and excellent low-temperature performance. In addition, the reaction kinetics and Li/Na-insertion/extraction mechanism into/out NVPOF is preliminarily investigated by the galvanostatic intermittent titration technique and ex situ X-ray diffraction. This work provides a new and profound direction to develop advanced hybrid batteries.A novel Li/Na-ion hybrid battery with high working voltage and superior electrochemical and low-temperature properties is designed and assembled by using lithium-free Na3V2(PO4)2O2F (NVPOF) and commercial graphite as cathode and anode, respectively. The electrode kinetics and Li/Na-insertion/extraction processes into/out the NVPOF cathode are preliminarily studied by the galvanostatic intermittent titration technique and ex situ X-ray diffraction.
      PubDate: 2018-01-10T03:55:36.455-05:00
      DOI: 10.1002/aenm.201702504
  • Scavenging Wind Energy by Triboelectric Nanogenerators
    • Authors: Bo Chen; Ya Yang, Zhong Lin Wang
      Abstract: To meet future needs for clean and sustainable energy, tremendous progress has been achieved in development for scavenging wind energy. The most classical approach is to use the electromagnetic effect based wind turbine with a diameter of larger than 50 m and a weight of larger than 50 ton, and each of them could cost more than $0.5 M, which can only be installed in remote areas. Alternatively, triboelectric nanogenerators based on coupling of contact-electrification and electrostatic induction effects have been utilized to scavenge wind energy, which takes the advantages of high voltage, low cost, and small size. Here, the development of a wind-driven triboelectric nanogenerator by focusing on triboelectric materials optimization, structure improvement, and hybridization with other types of energy harvesting techniques is reviewed. Moreover, the major applications are summarized and the challenges that are needed to be addressed and development direction for scavenging wind energy in future are highlighted.Triboelectric nanogenerators have been utilized to scavenge wind energy by coupling contact-electrification and electrostatic induction effects, where these devices have advantages of high voltage, low cost, and small size as compared with conventional electromagnetic effect-based wind turbines.
      PubDate: 2018-01-09T05:37:12.663184-05:
      DOI: 10.1002/aenm.201702649
  • Recent Progress in Ternary Organic Solar Cells Based on Nonfullerene
    • Authors: Runnan Yu; Huifeng Yao, Jianhui Hou
      Abstract: The use of a ternary component is a facile and effective method to further improve the device performances of binary organic solar cells (OSCs) comprising one donor and one acceptor. Recently, the rapid progress of highly efficient nonfullerene acceptor materials has offered a new opportunity for studying ternary OSCs because of the flexibility of ternary components, and the photovoltaic performance of ternary OSCs has been promoted quickly. In this research news article, some strategies for materials selection of the ternary components are concisely summarized and the recent progress in ternary OCSs based on nonfullerene acceptors, and the challenges and perspectives of ternary OSCs are also presented.Fullerene-free ternary organic solar cells integrating complementary absorptions are greatly inspired by the prosperous development of nonfullerene acceptors with their great performance and abundant varieties. This research news demonstrates the main functions of third components and some design guidelines for ternary composition and summarizes the recent advanced progress for high-performance ternary organic solar cells based on nonfullerene acceptors.
      PubDate: 2018-01-09T05:36:30.052166-05:
      DOI: 10.1002/aenm.201702814
  • Less is More: Dopant-Free Hole Transporting Materials for High-Efficiency
           Perovskite Solar Cells
    • Authors: Weiqi Zhou; Zhenhai Wen, Peng Gao
      Abstract: Perovskite solar cells have delivered power conversion efficiency beyond 22% in less than seven years, implying the potential for the paradigm shift of low-cost photovoltaics with high efficiency and low embedded energy. Besides the “perovskite fever,” the development of new hole transport materials (HTM), especially dopant-free HTMs, is another research hotspot. This is because the currently used HTMs, such as spiro-OMeTAD derivatives, require additional chemical doping process to ensure sufficient conductivity and proper ionic potential level for efficient hole transport and collection. However, the commonly used dopants are volatile and hygroscopic which not only increase the complexity and cost of device fabrication but also deteriorate the device stability. So far, there have been several reviews on new HTMs, but review or analysis on dopant-free HTMs is scarce. In this review, all reported dopant-free HTMs are categorized into four primary different types and lessons will be learned during the separate discussions. The stability test behavior of all the intrinsic HTMs will be evaluated directly. In the end, the correlations between the properties of the intrinsic HTMs and parameters of the devices will be plotted to shed light on the future direction of development of this field.Chemical dopants inside organic semiconductor are however not chemically bonded to the matrix. Their hydrophilic and mobile nature plays a significant role in the degradation of the perovskite devices. Dopant free HTMs are of great importance for the final application of this new PV technology.
      PubDate: 2018-01-08T09:31:29.51598-05:0
      DOI: 10.1002/aenm.201702512
  • High-Efficiency Polymer Homo-Tandem Solar Cells with Carbon
           Quantum-Dot-Doped Tunnel Junction Intermediate Layer
    • Authors: Rakwon Kang; Sujung Park, Yun Kyung Jung, Dong Chan Lim, Myung Joo Cha, Jung Hwa Seo, Shinuk Cho
      Abstract: The tunnel junction (TJ) intermediate connection layer (ICL), which is the most critical component for high-efficient tandem solar cell, generally consists of hole conducting layer and polyethyleneimine (PEI) polyelectrolyte. However, because of the nonconducting feature of pristine PEI, photocurrent is open-restricted in ICL even with a little thick PEI layer. Here, high-efficiency homo-tandem solar cells are demonstrated with enhanced efficiency by introducing carbon quantum dot (CQD)-doped PEI on TJ–ICL. The CQD-doped PEI provides substantial dynamic advantages in the operation of both single-junction solar cells and homo-tandem solar cells. The inclusion of CQDs in the PEI layer leads to improved electron extraction property in single-junction solar cells and better series connection in tandem solar cells. The highest efficient solar cell with CQD-doped PEI layer in between indium tin oxide (ITO) and photoactive layer exhibits a maximum power conversion efficiency (PCE) of 9.49%, which represents a value nearly 10% higher than those of solar cells with pristine PEI layer. In the case of tandem solar cells, the highest performing tandem solar cell fabricated with C-dot-doped PEI layer in ICL yields a PCE of 12.13%; this value represents an ≈15% increase in the efficiency compared with tandem solar cells with a pristine PEI layer.High-efficiency homo-tandem solar cells with enhanced power conversion efficiency (PCE) are demonstrated by introducing carbon quantum dot (CQD)-doped PEI on a tunnel junction intermediate connection layer. The inclusion of CQDs in the PEI layer leads to improved electron extraction properties and better series connection. The best tandem solar cell fabricated with the CQD-doped PEI layer yields a PCE of 12.13%.
      PubDate: 2018-01-08T02:37:01.648763-05:
      DOI: 10.1002/aenm.201702165
  • Enhanced Ion Conductivity in Conducting Polymer Binder for
           High-Performance Silicon Anodes in Advanced Lithium-Ion Batteries
    • Authors: Wenwu Zeng; Lei Wang, Xiang Peng, Tiefeng Liu, Youyu Jiang, Fei Qin, Lin Hu, Paul K. Chu, Kaifu Huo, Yinhua Zhou
      Abstract: Polymer binders with high ion and electron conductivities are prepared by assembling ionic polymers (polyethylene oxide and polyethylenimine) onto the electrically conducting polymer poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) chains. Crosslinking, chemical reductions, and electrostatics increase the modulus of the binders and maintain the integrity of the anode. The polymer binder shows lithium-ion diffusivity and electron conductivity that are 14 and 90 times higher than those of the widely used carboxymethyl cellulose (with acetylene black) binder, respectively. The silicon anode with the polymer binder has a high reversible capacity of over 2000 mA h g−1 after 500 cycles at a current density of 1.0 A g−1 and maintains a superior capacity of 1500 mA h g−1 at a high current density of 8.0 A g−1.A novel polymer binder with high ion and electron conductivities that are 14 and 90 times higher than those of the widely used carboxymethyl cellulose (with acetylene black) binder, respectively, is achieved. Crosslinking, chemical reductions, and electrostatics increase the modulus of the binders and maintain the integrity of the anode that contributes to the enhanced electrochemical performance.
      PubDate: 2018-01-08T02:36:32.048607-05:
      DOI: 10.1002/aenm.201702314
  • Tunable and Efficient Tin Modified Nitrogen-Doped Carbon Nanofibers for
           Electrochemical Reduction of Aqueous Carbon Dioxide
    • Authors: Yong Zhao; Jiaojiao Liang, Caiyun Wang, Jianmin Ma, Gordon G. Wallace
      Abstract: Efficient and selective earth-abundant catalysts are highly desirable to drive the electrochemical conversion of CO2 into value-added chemicals. In this work, a low-cost Sn modified N-doped carbon nanofiber hybrid catalyst is developed for switchable CO2 electroreduction in aqueous medium via a straightforward electrospinning technique coupled with a pyrolysis process. The electrocatalytic performance can be tuned by the structure of Sn species on the N-doped carbon nanofibers. Sn nanoparticles drive efficient formate formation with a high current density of 11 mA cm−2 and a faradaic efficiency of 62% at a moderate overpotential of 690 mV. Atomically dispersed Sn species promote conversion of CO2 to CO with a high faradaic efficiency of 91% at a low overpotential of 490 mV. The interaction between Sn species and pyridinic-N may play an important role in tuning the catalytic activity and selectivity of these two materials.A tunable Sn modified N-doped carbon nanofiber hybrid catalyst is developed for aqueous CO2 electroreduction. It can efficiently catalyze CO2 to formate or CO by the selective presence of Sn nanoparticles or atoms on the surface of pyridinic-N doped carbon nanofibers. This work may promote the development of nonprecious electrocatalysts for switchable conversion of CO2 to valuable products.
      PubDate: 2018-01-05T10:21:55.056676-05:
      DOI: 10.1002/aenm.201702524
  • A Biobased Composite Gel Polymer Electrolyte with Functions of Lithium
           Dendrites Suppressing and Manganese Ions Trapping
    • Authors: Ming Zhu; Jiaxin Wu, Wei-Hong Zhong, Jinle Lan, Gang Sui, Xiaoping Yang
      Abstract: Lithium (Li) dendrites in Li anodes, and dissolution and migration of manganese (Mn) ions in LiMn2O4 (LMO) cathodes, have hampered these extraordinary electrode materials from being efficiently applied in high performance Li batteries. Here, a novel, bifunctional, biobased composite gel polymer electrolyte (c-GPE) is created to simultaneously deal with the two critical issues. The skeleton of c-GPE is constructed from a sandwich structure composed of porous polydopamine spheres and two layers of the environmentally friendly soy protein isolate-based nanofiber membranes, and the carbonized polydopamine spheres are coated without any binder on the surface of the membranes. After a facile and innocuous preparation process, the skeleton material displays excellent thermal stability and good affinity to liquid electrolyte, which endows c-GPE with significant functions of effective mitigation of the dissolution of Mn ions, and chelation of the fleeing Mn ions, as well as the dramatic suppression of Li dendrite growth. Consequently, the LMO/Li batteries involving c-GPE show a great improvement in the cycling stability and rate performance compared with those of the cells based on commercial Celgard 2400. This work will be quite promising to meet the distinct requirements from Li batteries and provide a high-efficiency and safe biobased GPE for next generation energy storage systems.A biobased composite gel polymer electrolyte (c-GPE) is designed and successfully fabricated for suppressing lithium dendrites and tramping manganese ions simultaneously. The skeleton of the c-GPE consists of a layer of mesoporous polydopamine spheres, two layers of soy protein-based nanofiber membranes, and a layer of mesoporous carbonized polydopamine spheres.
      PubDate: 2018-01-05T10:21:27.946966-05:
      DOI: 10.1002/aenm.201702561
  • Masthead: (Adv. Energy Mater. 1/2018)
    • PubDate: 2018-01-05T08:46:18.800025-05:
      DOI: 10.1002/aenm.201870003
  • Composite Materials: Surface-Modified Porous Carbon Nitride Composites as
           Highly Efficient Electrocatalyst for Zn-Air Batteries (Adv. Energy Mater.
    • Authors: Wenhan Niu; Zhao Li, Kyle Marcus, Le Zhou, Yilun Li, Ruquan Ye, Kun Liang, Yang Yang
      Abstract: A rationally designed CoSx-C3N4-graphene composite displays excellent activity and stability toward oxygen evolution and reduction reactions, surpassing electrocatalytic performance shown by the state-of-the-art precious metal catalysts for Zn-air batteries. The remarkable performance of the developed air-electrode is attributed to the internally accessible electrochemical active sites and the facilitated transport of intermediates in the porous structure. This is reported by Yang Yang and co-workers in article number 1701642.
      PubDate: 2018-01-05T08:46:17.99863-05:0
      DOI: 10.1002/aenm.201870002
  • Batteries: 3D Porous Cu–Zn Alloys as Alternative Anode Materials for
           Li-Ion Batteries with Superior Low T Performance (Adv. Energy Mater.
    • Authors: Alberto Varzi; Luca Mattarozzi, Sandro Cattarin, Paolo Guerriero, Stefano Passerini
      Abstract: In article number 1701706, Alberto Varzi, Stefano Passerini, and co-workers report a novel class of lithium-ion battery (LIB) anodes based on Zn-rich porous CuxZn1-x intermetallic compounds. The carbon- and binder-free electrodes produced by cheap and scalable electrodeposition in aqueous media exhibit, in particular, an extraordinary lithium storage capability at low temperature. These findings may pave the way for more efficient, safer, and faster charging of LIB-powered vehicles in regions with cold climates.
      PubDate: 2018-01-05T08:46:17.346307-05:
      DOI: 10.1002/aenm.201870001
  • Excellence in Energy
    • Authors: Till von Graberg
      PubDate: 2018-01-05T08:46:15.2173-05:00
      DOI: 10.1002/aenm.201703350
  • Hydrogen Generation: Metal–Organic Framework Templated Porous
           Carbon-Metal Oxide/Reduced Graphene Oxide as Superior Support of
           Bimetallic Nanoparticles for Efficient Hydrogen Generation from Formic
           Acid (Adv. Energy Mater. 1/2018)
    • Authors: Fu-Zhan Song; Qi-Long Zhu, Xinchun Yang, Wen-Wen Zhan, Pradip Pachfule, Nobuko Tsumori, Qiang Xu
      Abstract: A metal–organic framework derived zirconia/porous carbon/reduced graphene oxide (ZrO2/C/rGO) nanocomposite as a superior support of bimetallic nanoparticles is reported in article number 1701416 by Qiang Xu and co-workers. The monodispersed PdAg NPs immobilized on ZrO2/C/rGO exhibit remarkable catalytic activity for hydrogen production from formic acid under mild conditions, rendered by the strong synergistic effect between metal NPs and support.
      PubDate: 2018-01-05T08:46:14.320704-05:
      DOI: 10.1002/aenm.201870006
  • Photocatalysis: Single-Crystalline Nanomesh Tantalum Nitride Photocatalyst
           with Improved Hydrogen-Evolving Performance (Adv. Energy Mater. 1/2018)
    • Authors: Mu Xiao; Bin Luo, Miaoqiang Lyu, Songcan Wang, Lianzhou Wang
      Abstract: In article number 1701605, Lianzhou Wang and co-workers report a new type of ultrathin Ta3N5 nanomesh with high specific surface area and excellent crystallinity by an innovative bottom-up graphene oxide templated strategy. The resulting Ta3N5 nanomeshes demonstrate drastically improved electron transport ability and prolonged lifetime of charge carriers, due to the nature of high surface area and excellent crystallinity. As a result, when used as photocatalysts, the Ta3N5 nanomeshes exhibit a greater than tenfold improvement in solar hydrogen production compared to bulk counterparts.
      PubDate: 2018-01-05T08:46:13.618633-05:
      DOI: 10.1002/aenm.201870005
  • Si-Doped Cu(In,Ga)Se2 Photovoltaic Devices with Energy Conversion
           Efficiencies Exceeding 16.5% without a Buffer Layer
    • Authors: Shogo Ishizuka; Jiro Nishinaga, Masayuki Iioka, Hirofumi Higuchi, Yukiko Kamikawa, Takashi Koida, Hajime Shibata, Paul Fons
      Abstract: In this communication, novel and simplified structure Cu(In,Ga)Se2 (CIGS) solar cells, which nominally consist of only a CIGS photoabsorber layer sandwiched between back and front contact layers but yet demonstrate high photovoltaic efficiencies, are reported. To realize this accomplishment, Si-doped CIGS films grown by the three-stage coevaporation method, B-doped ZnO transparent conductive oxide front contact layers deposited by chemical vapor deposition, and heat–light soaking treatments are used. Si-doping of CIGS films is found to modify the film surfaces and grain boundary properties and also affect the alkali metal distribution profiles in CIGS films. These effects are expected to contribute to improvements in buffer-free CIGS device performance. Heat–light soaking treatments, which are occasionally performed to improve conventional buffer-based CIGS device performance, are found to be also effective in enhancing buffer-free CIGS photovoltaic efficiencies. This result suggests that the mechanism behind the beneficial effects of heat–light soaking treatments originates from CIGS bulk issues and is independent of the buffer materials. Consequently, over 16.5% efficiencies, including an independently certified value, are demonstrated from completely buffer-free CIGS photovoltaic devices.Buffer-free simplified structure chalcogenide thin film solar cells with high efficiencies over 16.5% are demonstrated using novel Cu(In,Ga)Se2 (CIGS) photoabsorber layers grown with Si-doping. Heat–light soaking treatments boost device performance regardless of the use of buffer layers, implying that the light-induced metastable phenomena in CIGS devices originate from bulk CIGS rather than buffer layers or the CIGS/buffer interface.
      PubDate: 2018-01-05T05:52:08.856582-05:
      DOI: 10.1002/aenm.201702391
  • Kinetically Controlled Growth of Phase-Pure SnS Absorbers for Thin Film
           Solar Cells: Achieving Efficiency Near 3% with Long-Term Stability Using
           an SnS/CdS Heterojunction
    • Authors: Dongha Lim; Hoyoung Suh, Mahesh Suryawanshi, Gwang Yeom Song, Jae Yu Cho, Jin Hyeok Kim, Jae Hyuck Jang, Chan-Wook Jeon, Ara Cho, SeJin Ahn, Jaeyeong Heo
      Abstract: Facile control over the morphology of phase pure tin monosulfide (SnS) thin films, a promising future absorber for thin film solar cells, is enabled by controlling the growth kinetics in vapor transport deposition of congruently evaporated SnS. The pressure during growth is found to be a key factor in modifying the final shape of the SnS grains. The optimized cube-like SnS shows p-type with the apparent carrier concentration of ≈1017 cm−3 with an optical bandgap of 1.32 eV. The dense and flat surface morphology of 1 µm thick SnS combined with the minimization of pinholes directly leads to improved diode quality and increased shunt resistance of the SnS/CdS heterojunction (cell area of 0.30 cm2). An open-circuit voltage of up to 0.3068 V is achieved, which is independently characterized at the Korea Institute of Energy Research (KIER). Detailed high-resolution transmission electron microscopy analysis confirms the absence of detrimental secondary phases such as Sn2S3 or SnS2 in the SnS grains or at intergrain boundaries. The initial efficiency level of 98.5% is maintained even after six months of storage in air, and the final efficiency of the champion SnS/CdS cell, certified at the KIER, is 2.938% with an open-circuit voltage of 0.2912 V.Facile control on morphology of phase pure tin monosulfide (SnS) thin films is enabled by controlling the growth kinetics in vapor transport deposition. Dense and flat surface morphology of cube-like orthorhombic SnS combined with the minimized pinholes directly leads to improved diode quality and increased shunt resistance of the SnS/CdS heterojunction, achieving the certified efficiency of 2.938%.
      PubDate: 2018-01-03T05:27:09.284961-05:
      DOI: 10.1002/aenm.201702605
  • Tunable Free-Standing Ultrathin Porous Nickel Film for High Performance
           Flexible Nickel–Metal Hydride Batteries
    • Authors: Zhonghua Ren; Jie Yu, Yuanji Li, Chunyi Zhi
      Abstract: The nickel matrix has a significant impact on the structure and performance of a nickel–metal hydride (NiMH) battery. However, few studies have focused on the nickel matrix thus far due to the difficulty of fabricating controllable porous nickel materials. In addition, conventional nickel matrices show poor flexibility, making it difficult to fabricate flexible NiMH batteries. To achieve a high performance flexible NiMH battery, the fabrication of a thin, free-standing, and flexible nickel matrix with an optimized pore structure is a key prerequisite. Here, a novel flexible porous nickel matrix with a controllable pore size, density, and distribution of pore position is developed by nickel electrodeposition on templates that are produced by silkscreen printing different insulating ink microarrays on stainless steel sheets. Benefitting from the excellent structure of the porous nickel matrix, flexible NiMH batteries are fabricated, which show excellent flexibility and very high energy densities of 151.8 W h kg−1 and 508.5 W h L−1 as well as high energy efficiencies of 87.9–98.5%. These batteries outperform conventional NiMH batteries and many other commercial batteries, holding great promise for their future practical application. The present strategy provides a new route to promote the development of nickel-based alkaline rechargeable batteries.The first flexible solid-state nickel–metal hydride (NiMH) battery is developed by using a novel free-standing porous nickel matrix with tunable pore structures. The battery shows excellent flexibility and high energy densities of 151.8 W h kg−1 and 508.5 W h L−1 as well as high energy efficiencies of 87.9–98.5%, outperforming conventional NiMH batteries and many other commercial batteries.
      PubDate: 2018-01-03T05:26:24.998428-05:
      DOI: 10.1002/aenm.201702467
  • Coupled Supercapacitor and Triboelectric Nanogenerator Boost Biomimetic
           Pressure Sensor
    • Authors: Jingdian Zou; Meng Zhang, Jinrong Huang, Jie Bian, Yang Jie, Magnus Willander, Xia Cao, Ning Wang, Zhong Lin Wang
      Abstract: With the fast development of supercapacitor and triboelectric nanogenerator (TENG), it is now possible to fabricate biomimetic pressure sensors with high flexibility and sustainability. Herein, an ultrathin supercapacitor is fabricated with the paper sheet and the solid electrolyte for storing energy generated by TENG. With a sandwich design, the triboelectrodes sandwiched within the two solid supercapacitors can not only store electrical energy by a wireless energy transfer mode but also help TENG imitate the receptor's unique characteristics by simultaneously measuring both static and dynamic pressures in a self-driven mode. In addition, the voltage of the supercapacitor increases linearly with the vibration times, which hints that this integrated device also endows functions such as vibration counting and frequency computing. This work contributes to new strategies for making multifunctional biomimetic electronics that promote the development of artificial intelligence.An ultrathin self-powered biomimetic pressure sensor is demonstrated by integrating triboelectrodes of triboelectric nanogenerators within ultrathin supercapacitors. The pressure sensor can not only store electrical energy by a wireless energy transfer mode but also helps TENG imitate the receptor's unique characteristics by simultaneously measuring both static and dynamic pressures in a self-driven mode.
      PubDate: 2018-01-02T09:06:18.090646-05:
      DOI: 10.1002/aenm.201702671
  • Corrugation Architecture Enabled Ultraflexible Wafer-Scale High-Efficiency
           Monocrystalline Silicon Solar Cell
    • Authors: Rabab R. Bahabry; Arwa T. Kutbee, Sherjeel M. Khan, Adrian C. Sepulveda, Irmandy Wicaksono, Maha Nour, Nimer Wehbe, Amani S. Almislem, Mohamed T. Ghoneim, Galo A. Torres Sevilla, Ahad Syed, Sohail F. Shaikh, Muhammad M. Hussain
      Abstract: Advanced classes of modern application require new generation of versatile solar cells showcasing extreme mechanical resilience, large-scale, low cost, and excellent power conversion efficiency. Conventional crystalline silicon-based solar cells offer one of the most highly efficient power sources, but a key challenge remains to attain mechanical resilience while preserving electrical performance. A complementary metal oxide semiconductor-based integration strategy where corrugation architecture enables ultraflexible and low-cost solar cell modules from bulk monocrystalline large-scale (127 × 127 cm2) silicon solar wafers with a 17% power conversion efficiency. This periodic corrugated array benefits from an interchangeable solar cell segmentation scheme which preserves the active silicon thickness of 240 µm and achieves flexibility via interdigitated back contacts. These cells can reversibly withstand high mechanical stress and can be deformed to zigzag and bifacial modules. These corrugation silicon-based solar cells offer ultraflexibility with high stability over 1000 bending cycles including convex and concave bending to broaden the application spectrum. Finally, the smallest bending radius of curvature lower than 140 µm of the back contacts is shown that carries the solar cells segments.A corrugation architecture enabled ultraflexible, high performance crystalline-silicon solar cell on a 5 inch wafer via a lithography-less, complementary metal oxide semiconductor compatible technique, shows power conversion efficiency of 17.2%, a bending radius lower than 140 µm with the groove width of 0.86 mm, and a high mechanical stability over 1000 cyclic bending.
      PubDate: 2018-01-02T08:13:53.217895-05:
      DOI: 10.1002/aenm.201702221
  • Synergetic Protective Effect of the Ultralight MWCNTs/NCQDs Modified
           Separator for Highly Stable Lithium–Sulfur Batteries
    • Authors: Ying Pang; Jishi Wei, Yonggang Wang, Yongyao Xia
      Abstract: Lithium–sulfur (Li–S) batteries are highly attractive due to their high energy density, potentially low cost, and environmental compatibility. However, their commercialization has been greatly hindered by their poor cycle life and severe self-discharge, which can be attributed to the polysulfides dissolution. To overcome these issues, much effort has been devoted to engineering the electrode structure and composition to improve the performance which is often expensive and laborious. In this study, an ultralight multiwall carbon nanotube/N-doped carbon quantum dot (MWCNT/NCQD)-coated separator is first designed, which is cost effective and facile. The MWCNTs/NCQDs-coated separator is then applied in Li–S batteries. The MWCNTs/NCQDs coating provides a physical shield against polysulfide shuttling and chemical adsorption of polysulfides by MWCNTs and NCQDs. The synergetic effect of MWCNTs and NCQDs enables the production of Li–S cell with a relative high initial discharge capacity of 1330.8 mA h g−1 and excellent cyclic performance with a corresponding capacity fade rate of as low as 0.05% per cycle at 0.5 C over 1000 cycles. Excellent rate capability and anti-self-discharge behavior are also displayed. The design of MWCNTs/NCQDs-coated separator is a viable approach for successfully developing practical Li–S batteries.A novel multiwall carbon nanotube/N-doped carbon quantum dot coated separator is designed for a lithium–sulfur battery, which exhibits high capacity and excellent cyclability even at high current density.
      PubDate: 2018-01-02T08:12:41.422422-05:
      DOI: 10.1002/aenm.201702288
  • Enhanced Cyclability of Lithium–Oxygen Batteries with Electrodes
           Protected by Surface Films Induced via In Situ Electrochemical Process
    • Authors: Bin Liu; Wu Xu, Jinhui Tao, Pengfei Yan, Jianming Zheng, Mark H. Engelhard, Dongping Lu, Chongmin Wang, Ji-Guang Zhang
      Abstract: Although the rechargeable lithium–oxygen (Li–O2) batteries have extremely high theoretical specific energy, the practical application of these batteries is still limited by the instability of their carbon-based air-electrode, Li metal anode, and electrodes, toward reduced oxygen species. Here a simple one-step in situ electrochemical precharging strategy is demonstrated to generate thin protective films on both carbon nanotubes (CNTs), air-electrodes and Li metal anodes simultaneously under an inert atmosphere. Li–O2 cells after such pretreatment demonstrate significantly extended cycle life of 110 and 180 cycles under the capacity-limited protocol of 1000 mA h g−1 and 500 mA h g−1, respectively, which is far more than those without pretreatment. The thin-films formed from decomposition of electrolyte during in situ electrochemical precharging processes in an inert environment, can protect both CNTs air-electrode and Li metal anode prior to conventional Li–O2 discharge/charge cycling, where reactive reduced oxygen species are formed. This work provides a new approach for protection of carbon-based air-electrodes and Li metal anodes in practical Li–O2 batteries, and may also be applied to other battery systems.A novel in situ one-step electrochemical treatment strategy to simultaneously fabricate protective surface films on carbon-based air-electrodes and Li metal anodes initiates continuous protection for both electrodes, as well as promoting significantly enhanced cycling stability of Li–O2 batteries. This work presents an efficient method to address the instability issues associated with carbon-based electrodes and Li metal anodes in Li–O2 batteries.
      PubDate: 2018-01-02T08:07:23.7189-05:00
      DOI: 10.1002/aenm.201702340
  • Solar-Light-Driven CO2 Reduction by CH4 on Silica-Cluster-Modified Ni
           Nanocrystals with a High Solar-to-Fuel Efficiency and Excellent Durability
    • Authors: Hui Huang; Mingyang Mao, Qian Zhang, Yuanzhi Li, Jilin Bai, Yi Yang, Min Zeng, Xiujian Zhao
      Abstract: Catalytic CO2 reforming of CH4 (CRM) to produce syngas (H2 and CO) provides a promising approach to reducing global CO2 emissions and the extensive utilization of natural gas resources. However, the rapid deactivation of the reported catalysts due to severe carbon deposition at high reaction temperatures and the large energy consumption of the process hinder its industrial application. Here, a method for almost completely preventing carbon deposition is reported by modifying the surface of Ni nanocrystals with silica clusters. The obtained catalyst exhibits excellent durability for CRM with almost no carbon deposition and deactivation after reaction for 700 h. Very importantly, it is found that CRM on the catalyst can be driven by focused solar light, thus providing a promising new approach to the conversion of renewable solar energy to fuel due to the highly endothermic characteristics of CRM. The reaction yields high production rates of H2 and CO (17.1 and 19.9 mmol min−1 g−1, respectively) with a very high solar-to-fuel efficiency (η, 12.5%). Even under focused IR irradiation with a wavelength above 830 nm, the η of the catalyst remains as high as 3.1%. The highly efficient catalytic activity arises from the efficient solar-light-driven thermocatalytic CRM enhanced by a novel photoactivation effect.A unique nanocomposite is reported consisting of Ni nanocrystals modified with silica clusters. The nanocomposite exhibits high catalytic activity and excellent durability for CO2 reduction by methane under focused solar light. It yields high production rates of H2 and CO with 12.5% solar-to-fuel efficiency. The high catalytic activity arises from the solar-light-driven thermocatalysis enhanced by a novel photoactivation effect.
      PubDate: 2018-01-02T08:06:28.077046-05:
      DOI: 10.1002/aenm.201702472
  • Mimic the Photosystem II for Water Oxidation in Neutral Solution: A Case
           of Co3O4
    • Authors: Bing Ni; Kai Wang, Ting He, Yue Gong, Lin Gu, Jing Zhuang, Xun Wang
      Abstract: The photosystem II (PSII) in green plants exhibits marvelous oxygen production in neutral environments. However, artificially developed oxygen evolution catalysts (OECs) show much less activity, and the oxygen evolution reaction (OER) is now becoming a bottleneck in many energy-related issues. Here, the PSII is mimicked to design an efficient OER system in neutral environments by introducing an oleylamine (OAm) organic layer to cap the Co3O4 OEC, and employing buffers as proton shuttles in the system. Consequently, the activity is largely enhanced. The current density can reach 10 mA cm−2 at an overpotential (η) of 390 mV in the best case in neutral environment. The turnover frequency is 0.0117 at η of 400 mV, almost the same as that in 1 m KOH solutions. The surface chemistry of the Co3O4 OEC indicates that the OAm can promote the activity. The reason that buffers as proton shuttles can greatly facilitate the reaction is ascribed to the proton-coupled electron transfer process in the OER mechanism. These results may stimulate new perspectives on mimicking natural systems as well as new insights in electrocatalysis.Photosystem II is mimicked to design an efficient OER system in neutral environments by introducing an oleylamine layer to cap the Co3O4 nanoparticles, and employing buffers as proton shuttles in the system. The surface chemistry indicates that oleylamine can promote the activity. The reason that buffers can facilitate the reaction is ascribed to the proton-coupled electron transfer processes.
      PubDate: 2018-01-02T08:06:04.185535-05:
      DOI: 10.1002/aenm.201702313
  • Sodium Ion Stabilized Vanadium Oxide Nanowire Cathode for High-Performance
           Zinc-Ion Batteries
    • Authors: Pan He; Guobin Zhang, Xiaobin Liao, Mengyu Yan, Xu Xu, Qinyou An, Jun Liu, Liqiang Mai
      Abstract: Aqueous Zn-ion batteries (ZIBs) have received incremental attention because of their cost-effectiveness and the materials abundance. They are a promising choice for large-scale energy storage applications. However, developing suitable cathode materials for ZIBs remains a great challenge. In this work, pioneering work on the designing and construction of aqueous Zn//Na0.33V2O5 batteries is reported. The Na0.33V2O5 (NVO) electrode delivers a high capacity of 367.1 mA h g−1 at 0.1 A g−1, and exhibits long-term cyclic stability with a capacity retention over 93% for 1000 cycles. The improvement of electrical conductivity, resulting from the intercalation of sodium ions between the [V4O12]n layers, is demonstrated by single nanowire device. Furthermore, the reversible intercalation reaction mechanism is confirmed by X-ray diffraction, Raman, X-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy analysis. The outstanding performance can be attributed to the stable layered structure and high conductivity of NVO. This work also indicates that layered structural materials show great potential as the cathode of ZIBs, and the indigenous ions can act as pillars to stabilize the layered structure, thereby ensuring an enhanced cycling stability.An aqueous Zn//Na0.33V2O5 battery is designed, which comprises of a Na0.33V2O5 cathode, a zinc anode, and a mild aqueous electrolyte. The battery delivers a high capacity and exhibits long-term cyclic stability owing to the stable layered structure and high conductivity of Na0.33V2O5.
      PubDate: 2018-01-02T08:03:15.491568-05:
      DOI: 10.1002/aenm.201702463
  • Highly Defective Layered Double Perovskite Oxide for Efficient Energy
           Storage via Reversible Pseudocapacitive Oxygen-Anion Intercalation
    • Authors: Yu Liu; Zhenbin Wang, Jean-Pierre Marcel Veder, Zhenye Xu, Yijun Zhong, Wei Zhou, Moses O. Tade, Shaobin Wang, Zongping Shao
      Abstract: The use of perovskite materials as anion-based intercalation pseudocapacitor electrodes has received significant attention in recent years. Notably, these materials, characterized by high oxygen vacancy concentrations, do not require high surface areas to achieve a high energy storage capacity as a result of the bulk intercalation mechanism. This study reports that reduced PrBaMn2O6–δ (r-PBM), possessing a layered double perovskite structure, exhibits ultrahigh capacitance and functions as an excellent oxygen anion-intercalation-type electrode material for supercapacitors. Formation of the layered double perovskite structure, as facilitated by hydrogen treatment, is shown to significantly enhance the capacitance, with the resulting r-PBM material demonstrating a very high gravimetric capacitance of 1034.8 F g−1 and an excellent volumetric capacitance of ≈2535.3 F cm−3 at a current density of 1 A g−1. The resultant formation of a double perovskite crystal oxide with a specific layered structure leads to the r-PBM with a substantially higher oxygen diffusion rate and oxygen vacancy concentration. These superior characteristics show immense promise for their application as oxygen anion-intercalation-type electrodes in pseudocapacitors.The formation of a double perovskite crystal oxide with a specific layered structure results in the reduced PrBaMn2O6-δ (r-PBM) with a substantially higher oxygen diffusion rate and oxygen vacancy concentration. These factors are highly beneficial to the oxygen vacancies as charge storage sites can be applied in the pseudocapacitors with an oxygen ion intercalation process.
      PubDate: 2018-01-02T07:56:50.542032-05:
      DOI: 10.1002/aenm.201702604
  • Integration of FeOOH and Zeolitic Imidazolate Framework-Derived Nanoporous
           Carbon as an Efficient Electrocatalyst for Water Oxidation
    • Authors: Fei Li; Jian Du, Xiaona Li, Junyu Shen, Yong Wang, Yong Zhu, Licheng Sun
      Abstract: As a cost-effective catalyst for the oxygen evolution reaction (OER), the potential use of FeOOH is hindered by its intrinsic poor electron conductivity. Here, the significant enhancement of OER activity and long-term stability of electrodeposited FeOOH on zeolitic imidazolate framework-derived N-doped porous carbons (NPCs) are reported. In alkaline media, FeOOH/NPC supported on nickel foam as a 3D electrode delivers a current density of 100 mA cm−2 at a small overpotential of 230 mV and exhibits a low Tafel slope of 33.8 mV dec−1 as well as excellent durability, making it one of the most active OER catalysts. Such high performance is attributed to a combined effect of the excellent electron conductivity of NPC and the synergy between FeOOH and NiO derived from Ni substrate.The oxygen evolution reaction electrocatalyst is fabricated by electrodeposition of FeOOH on zeolitic imidazolate framework-derived N-doped porous carbon (NPC). The incorporation of a porous carbon layer with FeOOH greatly improves the electron conductivity of the hybrid material. FeOOH/NPC supported on nickel foam delivers a current density of 100 mA cm−2 at an overpotential of 230 mV with excellent durability.
      PubDate: 2018-01-02T07:55:54.775729-05:
      DOI: 10.1002/aenm.201702598
  • Jabuticaba-Inspired Hybrid Carbon Filler/Polymer Electrode for Use in
           Highly Stretchable Aqueous Li-Ion Batteries
    • Authors: Woo-Jin Song; Jeonghwan Park, Dong Hyup Kim, Sohyun Bae, Myung-Jun Kwak, Myoungsoo Shin, Sungho Kim, Sungho Choi, Ji-Hyun Jang, Tae Joo Shin, So Youn Kim, Kwanyong Seo, Soojin Park
      Abstract: Stretchable electronics are considered as next-generation devices; however, to realize stretchable electronics, it is first necessary to develop a deformable energy device. Of the various components in energy devices, the fabrication of stretchable current collectors is crucial because they must be mechanically robust and have high electrical conductivity under deformation. In this study, the authors present a conductive polymer composite composed of Jabuticaba-like hybrid carbon fillers containing carbon nanotubes and carbon black in a simple solution process. The hybrid carbon/polymer (HCP) composite is found to effectively retain its electrical conductivity, even when under high strain of ≈200%. To understand the behavior of conductive fillers in the polymer matrix when under mechanical strain, the authors investigate the microstructure of the composite using an in situ small-angle X-ray scattering analysis. The authors observe that the HCP produces efficient electrical pathways for filler interconnections upon stretching. The authors develop a stretchable aqueous rechargeable lithium-ion battery (ARLB) that utilizes this HCP composite as a stretchable current collector. The ARLB exhibits excellent rate capability (≈90 mA h g−1 at a rate of 20 C) and outstanding capacity retention of 93% after 500 cycles. Moreover, the stretchable ARLB is able to efficiently deliver power even when under 100% strain.Jabuticaba-like carbon filler/polymer composite is demonstrated as a stretchable electrode with excellent mechanical durability under strain. The percolation behavior of conductive fillers is determined using in situ small angle X-ray scattering. We have developed stretchable aqueous Li-ion batteries with high performance (~90 mA h g−1 at a rate of 20 C and capacity retention of 80% at a strain of 100%).
      PubDate: 2018-01-02T07:51:50.337894-05:
      DOI: 10.1002/aenm.201702478
  • Mechanical Property Evolution of Silicon Composite Electrodes Studied by
           Environmental Nanoindentation
    • Authors: Yikai Wang; Qinglin Zhang, Dawei Li, Jiazhi Hu, Jiagang Xu, Dingying Dang, Xingcheng Xiao, Yang-Tse Cheng
      Abstract: Mechanical degradation is largely responsible for the short cycle life of silicon (Si)-based electrodes for future lithium-ion batteries. An improved fundamental understanding of the mechanical behavior of Si electrodes, which evolves, as demonstrated in this paper, with the state of charge (SOC) and the cycle number, is a prerequisite for overcoming mechanical degradation and designing high capacity and durable Si-based electrodes. In this study, Young's modulus (E) and hardness (H) of Si composite electrodes at different SOCs and after different cycle numbers are measured by nanoindentation under both dry and wet (liquid electrolyte) conditions. Unlike electrodes made of Si alone, E and H values of Si composite electrodes increase with increasing Li concentration. The composite electrodes under wet conditions are softer than that under dry conditions. Both E and H decrease with the cycle number. These findings highlight the effects of porosity, liquid environment, and degradation on the mechanical behavior of composite electrodes. The methods and results of this study on the mechanical property evolution of Si/polyvinylidene fluoride electrodes form a basis for exploring more effective binders for Si-based electrodes. Furthermore, the evolving nature of the mechanical behavior of composite electrodes should be taken into consideration in future modeling efforts of porous composite electrodes.Young's modulus and hardness of Si composite electrodes vs the state of charge (SOC) and cycle number are measured by nanoindentation under both dry and wet conditions. In contrast to Si films, Young's Modulus (E) and hardness (H) of Si composite electrodes increase with increasing Li concentration. E and H values at the same SOC decrease with increasing cycle number.
      PubDate: 2018-01-02T07:51:18.210004-05:
      DOI: 10.1002/aenm.201702578
  • Chemically Exfoliating Biomass into a Graphene-like Porous Active Carbon
           with Rational Pore Structure, Good Conductivity, and Large Surface Area
           for High-Performance Supercapacitors
    • Authors: Shi-Yu Lu; Meng Jin, Yan Zhang, Yu-Bing Niu, Jie-Chang Gao, Chang Ming Li
      Abstract: Active carbons have unique physicochemical properties, but their conductivities and surface to weight ratios are much poorer than graphene. A unique and facile method is innovated to chemically process biomass by “drilling” holes with H2O2 and exfoliating into graphene-like nanosheets with HAc, followed by carbonization at a high temperature for highly graphitized activated carbon with greatly enhanced porosity, unique pore structure, high conductivity, and large surface area. This graphene-like carbon exhibits extremely high specific capacitance (340 F g−1 at 0.5 A g−1) and high specific energy density (23.33 to 16.67 W h kg−1) with excellent rate capability and long cycling stability (remains 98% after 10 000 cycles), which is much superior to all reported carbons including graphene. Synthesis mechanism for deriving biomass into porous graphene-like carbons is discussed in detail. The enhancement mechanism for the porous graphene-like carbon electrode reveals that rationally designed meso- and macropores are very critical in porous electrode performance, which can network micropores for diffusion freeways, high conductivity, and high utilization. This work has universal significance in producing highly porous and conductive carbons from biomass including biowastes for various energy storage/conversion applications.A graphene-like porous activated carbon derived from a biomass fabricated, rationally designed chemical process, followed by carbonization at high temperature, exhibits a specific capacitance of 340 F g−1 at 0.5 A g−1 and high specific energy density (23.33–16.67 W h kg−1), with excellent capacity retention after 10 000 cycles, superior to other carbon electrodes.
      PubDate: 2017-12-29T02:32:08.778173-05:
      DOI: 10.1002/aenm.201702545
  • Doping of [In2(phen)3Cl6]·CH3CN·2H2O Indium-Based Metal–Organic
           Framework into Hole Transport Layer for Enhancing Perovskite Solar Cell
    • Authors: Mengru Li; Debin Xia, Yulin Yang, Xi Du, Guohua Dong, Aifeng Jiang, Ruiqing Fan
      Abstract: Perovskite solar cells (PSCs) have gained a promising position during the past few years. However, as far as it goes, there is rare combination of the merits of metal–organic framework with PSCs. In this work, a 3D metal–organic framework, namely, [In2(phen)3Cl6]·CH3CN·2H2O (In2) is first introduced into hole transport material of PSCs through band alignment engineering. By this facile strategy, the pinholes in the hole transport layer are effectively reduced, and the migration of Au into the entire PSC structure can be alleviated simultaneously. Meanwhile, In2 also plays a role in enhancing the light absorption of perovskite, which is due to: (1) the large particles of In2 acting as light scattering centers; (2) the emission wavelength of In2 is almost the same as the excitation wavelength of perovskite. Consequently, short-current density (Jsc), open circuit voltage (Voc), and fill factor (FF) gain a significant increase from 19.53 to 21.03 mA cm−2, 0.98 to 1.01 V, and 0.67 to 0.74, respectively. Thereby, the power conversion efficiency is remarkably enhanced from 12.8% to 15.8%. In the end, the stability of PSCs should also be improved.The addition of [In2(phen)3Cl6]·CH3CN·2H2O (In2) into the hole transport layer of perovskite solar cells (PSCs) through band alignment engineering is beneficial for charge transfer and restricts penetration of Au from back contact. Furthermore, the ultraviolet absorption, photoluminescence and light scattering properties of In2 can improve the light utilization of PSCs, leading to an increase in power conversion efficiency from 12.8% to 15.8%.
      PubDate: 2017-12-29T02:31:31.76396-05:0
      DOI: 10.1002/aenm.201702052
  • MoS2/Graphene Nanosheets from Commercial Bulky MoS2 and Graphite as Anode
           Materials for High Rate Sodium-Ion Batteries
    • Authors: Dan Sun; Delai Ye, Ping Liu, Yougen Tang, Jun Guo, Lianzhou Wang, Haiyan Wang
      Abstract: Tuning heterointerfaces between hybrid phases is a very promising strategy for designing advanced energy storage materials. Herein, a low-cost, high-yield, and scalable two-step approach is reported to prepare a new type of hybrid material containing MoS2/graphene nanosheets prepared from ball-milling and exfoliation of commercial bulky MoS2 and graphite. When tested as an anode material for a sodium-ion battery, the as-prepared MoS2/graphene nanosheets exhibit remarkably high rate capability (284 mA h g−1 at 20 A g−1 (≈30C) and 201 mA h g−1 at 50 A g−1 (≈75C)) and excellent cycling stability (capacity retention of 95% after 250 cycles at 0.3 A g−1). Detailed experimental measurements and density functional theory calculation reveal that the functional groups in 2D MoS2/graphene heterostructures can be well tuned. The impressive rate capacity of the as-prepared MoS2/graphene hybrids should be attributed to the heterostructures with a low degree of defects and residual oxygen containing groups in graphene, which subsequently improve the electronic conductivity of graphene and decrease the Na+ diffusion barrier at the MoS2/graphene interfaces in comparison with the acid treated one.A low-cost, high-yield, and scalable two-step approach is designed to prepare a new type of MoS2/graphene nanosheet hybrid directly from commercial bulky MoS2 and graphite. The newly prepared MoS2/graphene hybrids exhibit extraordinary rate capability (201 mA h g−1 at 75C) and excellent cycling stability as anode for sodium ion batteries. The performance of the nanosheets benefit from the well-tuned structural defects and residual oxygen-containing groups in MoS2/graphene heterostructure.
      PubDate: 2017-12-27T03:53:38.901615-05:
      DOI: 10.1002/aenm.201702383
  • Elastic Sandwich-Type rGO–VS2/S Composites with High Tap Density:
           Structural and Chemical Cooperativity Enabling Lithium–Sulfur Batteries
           with High Energy Density
    • Authors: Zhibin Cheng; Zhubing Xiao, Hui Pan, Shiqing Wang, Ruihu Wang
      Abstract: Driven by increasing demand for high-energy-density batteries for consumer electronics and electric vehicles, substantial progress is achieved in the development of long-life lithium–sulfur (Li–S) batteries. Less attention is given to Li–S batteries with high volume energy density, which is crucial for applications in compact space. Here, a series of elastic sandwich-structured cathode materials consisting of alternating VS2-attached reduced graphene oxide (rGO) sheets and active sulfur layers are reported. Due to the high polarity and conductivity of VS2, a small amount of VS2 can suppress the shuttle effect of polysulfides and improve the redox kinetics of sulfur species in the whole sulfur layer. Sandwich-structured rGO–VS2/S composites exhibit significantly improved electrochemical performance, with high discharge capacities, low polarization, and excellent cycling stability compared with their bare rGO/S counterparts. Impressively, the tap density of rGO–VS2/S with 89 wt% sulfur loading is 1.84 g cm−3, which is almost three times higher than that of rGO/S with the same sulfur content (0.63 g cm−3), and the volumetric specific capacity of the whole cell is as high as 1182.1 mA h cm−3, comparable with the state-of-the-art reported for energy storage devices, demonstrating the potential for application of these composites in long-life and high-energy-density Li–S batteries.The elastic sandwich-type composites of alternating reduced graphene oxide (rGO)–vanadium disulfide (VS2) sheets and pure sulfur layers are fabricated using conductive VS2 as a shape-directed agent. The rGO–VS2/S with an 89 wt% sulfur loading shows high tap density and striking volumetric specific capacity. The excellent electrochemical performance holds great potential for practical application in compact space.
      PubDate: 2017-12-27T03:52:57.266552-05:
      DOI: 10.1002/aenm.201702337
  • Analysis of Ion-Diffusion-Induced Interface Degradation in Inverted
           Perovskite Solar Cells via Restoration of the Ag Electrode
    • Authors: Hyunho Lee; Changhee Lee
      Abstract: Straightforward evidence for ion-diffusion-induced interfacial degradation in inverted perovskite solar cells is presented. Over 1000 h, solar cells inevitably undergo degradation, especially with respect to the current density and fill factor. The Ag electrode is peeled off and re-evaporated to investigate the effect of the Ag/[6,6]-phenyl C71 butyric acid methyl ester (PCBM) interfacial degradation on the photovoltaic performance at days 10 (240 h), 20 (480 h), 30 (720 h), and 40 (960 h). The power conversion efficiency increases after the Ag electrode restoration process. While the current density shows a slightly decreased value, the fill factor and open-circuit voltage increase for the new electrode devices. The decrease in the activation energy due to the restored Ag electrode induces recovery of the fill factor. The diffused I− ions react with the PCBM molecules, resulting in a quasi n-doping effect of PCBM. Upon electrode exchange, the reversible interaction between the iodine ions and PCBM causes current density variation. The disorder model for the open-circuit voltage over a wide range of temperatures explains the open-circuit voltage increase at every electrode exchange. Finally, the degradation mechanism of the inverted perovskite solar cell over 1000 h is described under the proposed recombination system.An interfacial degradation mechanism of inverted perovskite solar cells is proposed. The Ag electrode is peeled off and re-evaporated to investigate the [6,6]-phenyl C71 butyric acid methyl ester/Ag interfacial degradation. Through an electrode restoration process, the degradation sources are eliminated, and the photovoltaic parameter variation is explained in detail.
      PubDate: 2017-12-27T03:51:44.552662-05:
      DOI: 10.1002/aenm.201702197
  • Dual Anion–Cation Reversible Insertion in a Bipyridinium–Diamide Triad
           as the Negative Electrode for Aqueous Batteries
    • Authors: Sofia Perticarari; Yuman Sayed-Ahmad-Baraza, Chris Ewels, Philippe Moreau, Dominique Guyomard, Philippe Poizot, Fabrice Odobel, Joël Gaubicher
      Abstract: Aqueous batteries are an emerging candidate for low-cost and environmentally friendly grid storage systems. Designing such batteries from inexpensive, abundant, recyclable, and nontoxic organic active materials provides a logical step toward improving both the environmental and economic impact of these systems. Herein the first ever battery material that works with simultaneous uptake and release of both cations and anions is proposed by coupling p-type (bipyridinium) and n-type (naphthalene diimide) redox moieties. It represents one of a new family of electrode materials which demonstrates an optimal oxidation potential (−0.47 V vs saturated calomel electrode), extremely fast kinetics, a highly competitive capacity (63 mA h g−1 at 4C), and cyclability in both neutral Na+ and Mg2+ electrolytes of molar range concentration. Through a combination of UV–vis spectroelectrochemistry, electrochemical quartz-crystal microbalance, Operando synchrotron-X-ray diffraction, and density functional theory calculations a novel dual cation/anion insertion mechanism was proven and rationalized. Based on these findings, this innovative p/n-type product may well provide a viable option for use as a negative electrode material, thereby promoting the design of cutting-edge, low-cost, rocking-chair dual-ion aqueous batteries.The first ever battery material that works with simultaneous uptake and release of both cations and anions is proposed for low cost aqueous batteries. The two redox subunits p-type-bipyridinium and n-type-naphthalene-diimide synergistically cooperate during the electrochemical process, leading to highly competitive performance in both neutral Na+ and Mg2+ electrolytes. The novel insertion mechanism is rationalized by UV-spectroelectrochemistry, electrochemical quartz-crystal microbalance, Operando-synchrotron-X-ray diffraction, and density functional theory calculations.
      PubDate: 2017-12-27T03:50:59.340254-05:
      DOI: 10.1002/aenm.201701988
  • Revealing Pseudocapacitive Mechanisms of Metal Dichalcogenide
           SnS2/Graphene-CNT Aerogels for High-Energy Na Hybrid Capacitors
    • Authors: Jiang Cui; Shanshan Yao, Ziheng Lu, Jian-Qiu Huang, Woon Gie Chong, Francesco Ciucci, Jang-Kyo Kim
      Abstract: SnS2 nanoplatelet electrodes can offer an exceptionally high pseudocapacitance in an organic Na+ ion electrolyte system, but their underlying mechanisms are still largely unexplored, hindering the practical applications of pseudocapacitive SnS2 anodes in Na-ion batteries (SIBs) and Na hybrid capacitors (SHCs). Herein, SnS2 nanoplatelets are grown directly on SnO2/C composites to synthesize SnS2/graphene-carbon nanotube aerogel (SnS2/GCA) by pressurized sulfidation where the original morphology of carbon framework is preserved. The composite electrode possessing a large surface area delivers a remarkable specific capacity of 600.3 mA h g−1 at 0.2 A g−1 and 304.8 mA h g−1 at an ultrahigh current density of 10 A g−1 in SIBs. SHCs comprising a SnS2/GCA composite anode and an activated carbon cathode present exceptional energy densities of 108.3 and 26.9 W h kg−1 at power densities of 130 and 6053 W kg−1, respectively. The in situ transmission electron microscopy and the density functional theory calculations reveal that the excellent pseudocapacitance originates from the combination of Na adsorption on the surface/Sn edge of SnS2 nanoplatelets and ultrafast Na+ ion intercalation into the SnS2 layers.Metal dichalcogenide SnS2 nanoplatelets are synthesized by pressurized sulfidation and are anchored on graphene-carbon nanotube aerogels as anodes for Na-ion batteries and Na hybrid capacitors. The composite anode delivers an ultrahigh pseudocapacitance which originates from both Na+ ion intercalation into the SnS2 layers and adsorption of Na on the surface/Sn edge of SnS2 nanoplatelets.
      PubDate: 2017-12-27T03:48:24.009738-05:
      DOI: 10.1002/aenm.201702488
  • Antimonene: A Novel 2D Nanomaterial for Supercapacitor Applications
    • Authors: Emiliano Martínez-Periñán; Michael P. Down, Carlos Gibaja, Encarnación Lorenzo, Félix Zamora, Craig E. Banks
      Abstract: In pursuing higher energy density, without compromising the power density of supercapacitor platforms, the application of an advanced 2D nanomaterial is utilized to maximize performance. Antimonene, for the first time, is characterized as a material for applications in energy storage, being applied as an electrode material as the basis of a supercapacitor. Antimonene is shown to significantly improve the energy storage capabilities of a carbon electrode in both cyclic voltammetry and galvanostatic charging. Antimonene demonstrates remarkable performance with a capacitance of 1578 F g−1, with a high charging current density of 14 A g−1. Hence, antimonene is shown to be a highly promising material for energy storage applications. The system also demonstrates a highly competitive energy and power densities of 20 mW h kg−1 and 4.8 kW kg−1, respectively. In addition to the excellent charge storing abilities, antimonene shows good cycling capabilities.Advanced nanomaterials have significant potential for applications in the energy storage field. A very stable to operating conditions, novel nanomaterial is presented here, for the first time, as an electrode material for energy storage architectures. Antimonene, a single or few-layer material derived from bulk antimony, is, for the first time characterized as a nanomaterial suitable for energy storage applications.
      PubDate: 2017-12-22T07:20:50.694148-05:
      DOI: 10.1002/aenm.201702606
  • All-Oxide MoOx/SnOx Charge Recombination Interconnects for Inverted
           Organic Tandem Solar Cells
    • Authors: Tim Becker; Sara Trost, Andreas Behrendt, Ivan Shutsko, Andreas Polywka, Patrick Görrn, Philip Reckers, Chittaranjan Das, Thomas Mayer, Dario Di Carlo Rasi, Koen H. Hendriks, Martijn M. Wienk, René A. J. Janssen, Thomas Riedl
      Abstract: Multijunction solar cells are designed to improve the overlap with the solar spectrum and to minimize losses due to thermalization. Aside from the optimum choice of photoactive materials for the respective sub-cells, a proper interconnect is essential. This study demonstrates a novel all-oxide interconnect based on the interface of the high-work-function (WF) metal oxide MoOx and low-WF tin oxide (SnOx). In contrast to typical p-/n-type tunnel junctions, both the oxides are n-type semiconductors with a WF of 5.2 and 4.2 eV, respectively. It is demonstrated that the electronic line-up at the interface of MoOx and SnOx comprises a large intrinsic interface dipole (≈0.8 eV), which is key to afford ideal alignment of the conduction band of MoOx and SnOx, without the requirement of an additional metal or organic dipole layer. The presented MoOx/SnOx interconnect allows for the ideal (loss-free) addition of the open circuit voltages of the two sub-cells.A novel all-oxide recombination interconnect for organic tandem solar cells is reported. A large interface dipole between the high-work-function (WF) metal oxide MoOx and low-WF tin oxide (SnOx) affords ideal alignment of the conduction band of the two n-type metal oxides. The actual recombination of electrons with holes occurs at the interface of organic/MoOx of the lower sub-cell.
      PubDate: 2017-12-22T06:33:14.778065-05:
      DOI: 10.1002/aenm.201702533
  • Barium Bismuth Niobate Double Perovskite/Tungsten Oxide Nanosheet
           Photoanode for High-Performance Photoelectrochemical Water Splitting
    • Authors: Baicheng Weng; Corey R. Grice, Jie Ge, Tilak Poudel, Xunming Deng, Yanfa Yan
      Abstract: Recently, a new method to effectively engineer the bandgap of barium bismuth niobate (BBNO) double perovskite was reported. However, the planar electrodes based on BBNO thin films show low photocurrent densities for water oxidation owing to their poor electrical conductivity. Here, it is reported that the photoelectrochemical (PEC) activity of BBNO-based electrodes can be dramatically enhanced by coating thin BBNO layers on tungsten oxide (WO3) nanosheets to solve the poor conductivity issue while maintaining strong light absorption. The PEC activity of BBNO/WO3 nanosheet photoanodes can be further enhanced by applying Co0.8Mn0.2Ox nanoparticles as a co-catalyst. A photocurrent density of 6.02 mA cm−2 at 1.23 V (vs reversible hydrogen electrode (RHE)) is obtained using three optically stacked, but electrically parallel, BBNO/WO3 nanosheet photoanodes. The BBNO/WO3 nanosheet photoanodes also exhibit excellent stability in a high-pH alkaline solution; the photoanodes demonstrate negligible photocurrent density decay while under continuous PEC operation for more than 7 h. This work suggests a viable approach to improve the PEC performance of BBNO absorber-based devices.To overcome the low electric conductivity of Ba2Bi1.4Nb0.6O6 (BBNO) while maintaining strong light absorption, ultrathin BBNO layers are coated onto aligned WO3 nanosheets. With the application of Co0.8Mn0.2Ox catalyst, the optically stacked but electrically parallel BBNO nanostructured photoelectrodes achieve photocurrent densities up to 6.02 mA cm−2 at 1.23 V (vs RHE) with excellent stability.
      PubDate: 2017-12-22T06:32:22.195682-05:
      DOI: 10.1002/aenm.201701655
  • Significantly Enhancing the Efficiency of a New Light-Harvesting Polymer
           with Alkylthio naphthyl Substituents Compared to Their Alkoxyl Analogs
    • Authors: Gongyue Huang; Jun Zhang, Nergui Uranbileg, Weichao Chen, Huanxiang Jiang, Hua Tan, Weiguo Zhu, Renqiang Yang
      Abstract: In this work, a new benzo[1,2-b:4,5-b′]dithiophene (BDT) building block containing alkylthio naphthyl as a side chain is designed and synthesized, and the resulting polymer, namely PBDTNS-BDD, shows a lower HOMO energy level than that of its alkoxyl naphthyl counterpart PBDTNO-BDD. An optimized photovoltaic device using PBDTNS-BDD as a donor exhibits power conversion efficiencies (PCE) of 8.70% and 9.28% with the fullerene derivative PC71BM and the fullerene-free small molecule ITIC as acceptors, respectively. Surprisingly, ternary blend devices based on PBDTNS-BDD and two acceptors, namely PC71BM and ITIC, shows a PCE of 11.21%, which is much higher than that of PBDTNO-BDD based ternary devices (7.85%) even under optimized conditions.Ternary blend devices containing a new building block show much better power conversion efficiencies than their corresponding binary counterparts. These new building blocks contain alkylthio naphthyl as a side chain. Blending with two acceptors, PC71BM and ITIC, results in PBDTNS-BDD devices with a power conversion efficiency of 11.21%, which is much higher than that of the PBDTNO-BDD (7.85%) analogue under optimized conditions.
      PubDate: 2017-12-22T06:30:05.566686-05:
      DOI: 10.1002/aenm.201702489
  • Extended Light Harvesting with Dual Cu2O-Based Photocathodes for High
           Efficiency Water Splitting
    • Authors: Wenzhe Niu; Thomas Moehl, Wei Cui, René Wick-Joliat, Liping Zhu, Stanley David Tilley
      Abstract: Cu2O is one of the most promising light absorbing materials for solar energy conversion. Previous studies with Cu2O for water splitting usually deliver high photocurrent or high photovoltage, but not both. Here, a Cu2O/Ga2O3/TiO2/RuOx photocathode that benefits from a high quality thermally oxidized Cu2O layer and good band alignment of the Ga2O3 buffer layer is reported, yielding a photocurrent of 6 mA cm−2 at 0 V versus reversible hydrogen electrode (RHE), an onset potential of 0.9 V versus RHE, and 3.5 mA cm−2 at 0.5 V versus RHE. The quantum efficiency spectrum (incident photon to current efficiency, IPCE) reveals a dramatically improved green/red response and a decreased blue response compared with electrodeposited Cu2O films. Light intensity dependence and photocurrent transient studies enable the identification of the limitations in the performance. Due to the complementary IPCE curves of thermally oxidized and electrodeposited Cu2O photocathodes, a dual photocathode is fabricated to maximize the absorption over the entire range of above band gap radiation. Photocurrents of 7 mA cm−2 at 0 V versus RHE are obtained in the dual photocathodes, with an onset potential of 0.9 V versus RHE and a thermodynamically based energy conversion efficiency of 1.9%.Thermal oxidation of copper foils produces high quality Cu2O for high efficiency water splitting, with a dramatically improved photon conversion in the green and red portion of the absorption spectrum. By combining thermally oxidized with electrodeposited Cu2O in a dual photocathode configuration, high conversion efficiencies over the entire range of light absorption of Cu2O are obtained.
      PubDate: 2017-12-22T06:29:17.205479-05:
      DOI: 10.1002/aenm.201702323
  • All-Solution-Processed Silver Nanowire Window Electrode-Based Flexible
           Perovskite Solar Cells Enabled with Amorphous Metal Oxide Protection
    • Authors: Eunsong Lee; Jihoon Ahn, Hyeok-Chan Kwon, Sunihl Ma, Kyungmi Kim, Seongcheol Yun, Jooho Moon
      Abstract: Silver nanowire (AgNW)-based transparent electrodes prepared via an all-solution-process are proposed as bottom electrodes in flexible perovskite solar cells (PVSCs). To enhance the chemical stability of AgNWs, a pinhole-free amorphous aluminum doped zinc oxide (a-AZO) protection layer is deposited on the AgNW network. Compared to its crystalline counterpart (c-AZO), a-AZO substantially improves the chemical stability of the AgNW network. For the first time, it is observed that inadequately protected AgNWs can evanesce via diffusion, whereas a-AZO secures the integrity of AgNWs. When an optimally thick a-AZO layer is used, the a-AZO/AgNW/AZO composite electrode exhibits a transmittance of 88.6% at 550 nm and a sheet resistance of 11.86 Ω sq−1, which is comparable to that of commercial fluorine doped tin oxide. The PVSCs fabricated with a configuration of Au/spiro-OMeTAD/CH3NH3PbI3/ZnO/AZO/AgNW/AZO on rigid and flexible substrates can achieve power conversion efficiencies (PCEs) of 13.93% and 11.23%, respectively. The PVSC with the a-AZO/AgNW/AZO composite electrode retains 94% of its initial PCE after 400 bending iterations with a bending radius of 12.5 mm. The results clearly demonstrate the potential of AgNWs as bottom electrodes in flexible PVSCs, which can facilitate the commercialization and large-scale deployment of PVSCs.A pinhole-free amorphous Al-doped zinc oxide (AZO) protection layer dramatically enhances the chemical stability of silver nanowires (AgNWs). Using all-solution-processed amorphous AZO/AgNW/AZO transparent electrodes in flexible perovskite solar cells, it is possible to achieve a power conversion efficiency of 11.23%.
      PubDate: 2017-12-19T02:21:56.102589-05:
      DOI: 10.1002/aenm.201702182
  • Site-Selective In Situ Electrochemical Doping for Mn-Rich Layered Oxide
           Cathode Materials in Lithium-Ion Batteries
    • Authors: Aram Choi; Jungwoo Lim, Hyung-Jin Kim, Sung Chul Jung, Hyung-Woo Lim, Hanseul Kim, Mi-Sook Kwon, Young Kyu Han, Seung M. Oh, Kyu Tae Lee
      Abstract: Various doped materials have been investigated to improve the structural stability of layered transition metal oxides for lithium-ion batteries. Most doped materials are obtained through solid state methods, in which the doping of cations is not strictly site selective. This paper demonstrates, for the first time, an in situ electrochemical site-selective doping process that selectively substitutes Li+ at Li sites in Mn-rich layered oxides with Mg2+. Mg2+ cations are electrochemically intercalated into Li sites in delithiated Mn-rich layered oxides, resulting in the formation of [Li1−xMgy][Mn1−zMz]O2 (M = Co and Ni). This Mg2+ intercalation is irreversible, leading to the favorable doping of Mg2+ at the Li sites. More interestingly, the amount of intercalated Mg2+ dopants increases with the increasing amount of Mn in Li1−x[Mn1−zMz]O2, which is attributed to the fact that the Mn-to-O electron transfer enhances the attractive interaction between Mg2+ dopants and electronegative Oδ− atoms. Moreover, Mg2+ at the Li sites in layered oxides suppresses cation mixing during cycling, resulting in markedly improved capacity retention over 200 cycles. The first-principle calculations further clarify the role of Mg2+ in reduced cation mixing during cycling. The new concept of in situ electrochemical doping provides a new avenue for the development of various selectively doped materials.An in situ electrochemical site-selective doping method selectively substitutes Li+ at Li sites in Mn-rich layered oxides with Mg2+. Mg2+ is electrochemically and irreversibly intercalated into Li sites in delithiated Mn-rich layered oxides, resulting in the formation of Mg2+-doped layered oxides. The Mg2+ intercalation into the layered oxides strongly depends on the amount of Mn in the layered oxides.
      PubDate: 2017-12-19T02:21:17.774923-05:
      DOI: 10.1002/aenm.201702514
  • A Low-Temperature Thin-Film Encapsulation for Enhanced Stability of a
           Highly Efficient Perovskite Solar Cell
    • Authors: Young Il Lee; Nam Joong Jeon, Bong Jun Kim, Hyunjeong Shim, Tae-Youl Yang, Sang Il Seok, Jangwon Seo, Sung Gap Im
      Abstract: The stability of a perovskite solar cell (PSC) is enhanced significantly by applying a customized thin-film encapsulation (TFE). The TFE is composed of a multilayer stack of organic/inorganic layers deposited by initiated chemical vapor deposition and atomic layer deposition, respectively, whose water vapor transmission rate is on the order of 10−4 g m−2 d−1 at an accelerated condition of 38 °C and 90% relative humidity (RH). The TFE is optimized, taking into consideration various aspects of thermosensitive PSCs. Lowering the process temperature is one of the most effective methods for minimizing the thermal damage to the PSC during the monolithic integration of the TFE onto PSC. The direct deposition of TFE onto a PSC causes less than 0.3% degradation (from 18.5% to 18.2%) in the power conversion efficiency, while the long-term stability is substantially improved; the PSC retains 97% of its original efficiency after a 300 h exposure to an accelerated condition of 50 °C and 50% RH, confirming the enhanced stability of the PSC against moisture. This is the first demonstration of a TFE applied directly onto PSCs in a damage-free manner, which will be a powerful tool for the development of highly stable PSCs with high efficiency.The thin-film encapsulation (TFE) via initiated chemical deposition and low-temperature atomic layer deposition effectively enhances the stability of a high-efficient perovskite solar cell (PSC). The TFE is directly deposited onto the PSC without degradation, and the encapsulated PSC retains 97% of its original efficiency after a 300 h exposure to an accelerated condition of 50 °C and 50% relative humidity.
      PubDate: 2017-12-18T05:57:15.945821-05:
      DOI: 10.1002/aenm.201701928
  • In Situ EXAFS-Derived Mechanism of Highly Reversible Tin
           Phosphide/Graphite Composite Anode for Li-Ion Batteries
    • Authors: Yujia Ding; Zhe-Fei Li, Elena V. Timofeeva, Carlo U. Segre
      Abstract: A novel Sn4P3/graphite composite anode material with superior capacity and cycling performance (651 mA h g−1 after 100 cycles) is investigated by in situ X-ray absorption spectroscopy. Extended X-ray absorption fine structure modeling and detailed analysis of local environment changes are correlated to the cell capacity and reveal the mechanism of lithiation/delithiation process. Results show that in the first two lithiation/delithiation cycles crystalline Sn4P3 is fully converted to an amorphous SnPx phase, which in further cycles participates in reversible conversion and alloying reactions. The superior reversibility of this material is attributed to the highly dispersed SnPx in the graphite matrix, which provides enhanced electrical conductivity and prevents aggregation of Sn clusters during the lithiation/delithiation process. The gradual capacity fading in long-term cycling is attributed to the observed increase in the size and the amount of metallic Sn clusters in the delithiated state, correlated to the reduced recovery of the SnPx phase. This paper reveals the mechanism responsible for the highly reversible tin phosphides and provides insights for improving the capacity and cycle life of conversion and alloying materials.A novel Sn4P3/graphite composite anode for Li-ion batteries with high reversible capacity and cycle life is investigated with in situ X-ray absorption spectroscopy. The mechanism for reversible conversion and alloying reactions due to the amorphous SnPx phase and graphite matrix is proposed based on extended X-ray absorption fine structure (EXAFS) modeling results.
      PubDate: 2017-12-18T05:55:58.836367-05:
      DOI: 10.1002/aenm.201702134
  • Facile Metal Coordination of Active Site Imprinted Nitrogen Doped Carbons
           for the Conservative Preparation of Non-Noble Metal Oxygen Reduction
    • Authors: Asad Mehmood; Jonas Pampel, Ghulam Ali, Heung Yong Ha, Francisco Ruiz-Zepeda, Tim-Patrick Fellinger
      Abstract: Iron- or cobalt-coordinated heteroatom doped carbons are promising alternatives for Pt-based cathode catalysts in polymer-electrolyte fuel cells. Currently, these catalysts are obtained at high temperatures. The reaction conditions complicate the selective and concentrated formation of metal–nitrogen active sites. Herein a mild procedure is introduced, which is conservative toward the carbon support and leads to active-site formation at low temperatures in a wet-chemical metal-coordination step. Active-site imprinted nitrogen doped carbons are synthesized via ionothermal carbonization employing Lewis-acidic Mg2+ salt. The obtained carbons with large tubular porosity and imprinted N4 sites lead to very active catalysts with a half-wave potential (E1/2) of up to 0.76 V versus RHE in acidic electrolyte after coordination with iron. The catalyst shows 4e− selectivity and exceptional stability with a half-wave potential shift of only 5 mV after 1000 cycles. The X-ray absorption fine structure as well as the X-ray absorption near edge structure profiles of the most active catalyst closely match that of iron(II)phthalocyanine, proving the formation of active and stable FeN4 sites at 80 °C. Metal-coordination with other transition metals reveals that Zn–Nx sites are inactive, while cobalt gives rise to a strong performance increase even at very low concentrations.Nonprecious metal electrocatalysts consisting of transition iron–nitrogen (FeNx) active sites present a promising substitute for platinum-based oxygen reduction electrocatalysts. This study introduces a novel approach for synthesizing highly active and stable FeN4 sites by simple low temperature metal-coordination (metalation or transmetalation) of active site imprinted nitrogen doped carbons, fully preventing the formation of other undesired metal phases.
      PubDate: 2017-12-18T05:54:40.385855-05:
      DOI: 10.1002/aenm.201701771
  • Low-Dimensional Perovskites: From Synthesis to Stability in Perovskite
           Solar Cells
    • Authors: Abd. Rashid bin Mohd. Yusoff; Mohammad Khaja Nazeeruddin
      Abstract: Perovskite solar cells have been heralded as one of the most promising emerging technologies in 2016 because of the very high power conversion efficiency of 22% and the low cost of generating electricity compared to even fossil fuels. These are formed with various dimensionalities and can be fully manipulated once their bulk structure is reduced to a low-dimensional structure. Despite being one of the most attractive materials to date, their instability significantly influences device performance and subsequently prevents the timely commercialization of perovskite solar cell technology. In this review, the recent advances in the synthesis of stable low-dimensional metal-halide perovskites are highlighted.The recent advances in the synthesis of low-dimensional metal-halide perovskite and the sources of instability including water intercalation, ion migration, and thermal decomposition are shown.
      PubDate: 2017-12-18T05:52:25.457673-05:
      DOI: 10.1002/aenm.201702073
  • Spontaneous Growth of 3D Framework Carbon from Sodium Citrate for High
           Energy- and Power-Density and Long-Life Sodium-Ion Hybrid Capacitors
    • Authors: Bingjun Yang; Jiangtao Chen, Shulai Lei, Ruisheng Guo, Hongxia Li, Siqi Shi, Xingbin Yan
      Abstract: Carbon sheets with 3D architectures, large graphitic interlayer spacing, and high electrical conductivity are highly expected to be an ideal anode material for sodium-ion hybrid capacitors (SIHCs). Pursuing a simple synthesis methodology and advancing it from the laboratory to industry is of great importance. In this study, a new approach is presented to prepare 3D framework carbon (3DFC) with the above integrated advantages by a direct calcination of sodium citrate without aid of any additional carbon source, template, or catalyst. The first-principle calculations verify that the large interlayer spacing and the curvature structure of 3DFC facilitate the sodium ion insertion/extraction. As a consequence, the optimal 3DFC sample exhibits high reversible capacity as well as excellent rate and cycling performance. On this basis, a dual-carbon SIHC is fabricated by employing 3DFC as battery-type anode and 3DFC-derived nanoporous carbon as capacitor-type cathode. It is able to deliver high energy- and power-density feature as well as outstanding long-term cycling stability in the potential range of 0–4.0 V. This study may open an avenue for developing high-performance carbon electrode materials and pushes the practical applications of SIHCs a decisive step forward.A simple, low-cost, and large-scale preparation of 3D framework carbon (3DFC) with large interlayer spacing, curved interface, and high conductivity is proposed. The as-prepared 3DFC anode exhibits excellent sodium storage performance. On this basis, an advanced dual-carbon sodium-ion hybrid capacitor is fabricated by employing such 3DFC as battery-type anode and 3DFC-derived nanoporous carbon as capacitor-type cathode.
      PubDate: 2017-12-18T05:46:36.775728-05:
      DOI: 10.1002/aenm.201702409
  • Oriented Grains with Preferred Low-Angle Grain Boundaries in Halide
           Perovskite Films by Pressure-Induced Crystallization
    • Authors: Wanjung Kim; Myung Sun Jung, Seonhee Lee, Yung Ji Choi, Jung Kyu Kim, Sung Uk Chai, Wook Kim, Dae-Geun Choi, Hyungju Ahn, Jeong Ho Cho, Dukhyun Choi, Hyunjung Shin, Dongho Kim, Jong Hyeok Park
      Abstract: A general methodology is reported to create organic–inorganic hybrid metal halide perovskite films with enlarged and preferred-orientation grains. Simply pressing polyurethane stamps with hexagonal nanodot arrays on partially dried perovskite intermediate films can cause pressure-induced perovskite crystallization. This pressure-induced crystallization allows to prepare highly efficient perovskite solar cells (PSCs) because the preferred-orientation and enlarged grains with low-angle grain boundaries in the perovskite films exhibit suppressed nonradiative recombination. Consequently, the photovoltaic response is dramatically improved by the uniaxial compression in both inverted-planar PSCs and normal PSCs, leading to power conversion efficiencies of 19.16%.Mechanical crystallization methodology for preferred-orientation and close-packed grains of perovskite materials with uniaxial compression is achieved. Simply pressing polyurethane stamps with hexagonal nanodot arrays on partially dried perovskite intermediate films can cause pressure-induced perovskite crystallization, leading to preferred-orientation and enlarged grains with low-angle grain boundaries in the perovskite films. The photovoltaic response dramatically improves in both inverted-planar perovskite solar cells and normal perovskite solar cells, leading to a power conversion efficiency of 19.16%.
      PubDate: 2017-12-18T05:45:07.487883-05:
      DOI: 10.1002/aenm.201702369
  • Achieving zT > 2 in p-Type AgSbTe2−xSex Alloys via Exploring the Extra
           Light Valence Band and Introducing Dense Stacking Faults
    • Authors: Min Hong; Zhi-Gang Chen, Lei Yang, Zhi-Ming Liao, Yi-Chao Zou, Yan-Hui Chen, Syo Matsumura, Jin Zou
      Abstract: Through simultaneously enhancing the power factor by engineering the extra light band and enhancing phonon scatterings by introducing a high density of stacking faults, a record figure-of-merit over 2.0 is achieved in p-type AgSbTe2−xSex alloys. Density functional theory calculations confirm the presence of the light valence band with large degeneracy in AgSbTe2, and that alloying with Se decreases the energy offset between the light valence band and the valence band maximum. Therefore, a significantly enhanced power factor is realized in p-type AgSbTe2−xSex alloys. In addition, transmission electron microscopy studies indicate the appearance of stacking faults and grain boundaries, which together with grain boundaries and point defects significantly strengthen phonon scatterings, leading to an ultralow thermal conductivity. The synergetic strategy of simultaneously enhancing power factor and strengthening phonon scattering developed in this study opens up a robust pathway to tailor thermoelectric performance.The extra light valence band and dense stacking faults ensure a figure-of-merit over 2 in AgSbTe1.85Se0.15. Alloying with Se decreases the energy offset between the light and the primary valence bands, leading to an enhanced power factor. Transmission electron microscopy studies reveal the dense stacking faults and grain boundaries, which significantly strengthen phonon scatterings, generating an ultralow thermal conductivity.
      PubDate: 2017-12-18T05:44:23.673542-05:
      DOI: 10.1002/aenm.201702333
  • Voltage Losses in Organic Solar Cells: Understanding the Contributions of
           Intramolecular Vibrations to Nonradiative Recombinations
    • Authors: Xian-Kai Chen; Jean-Luc Brédas
      Abstract: The large voltage losses usually encountered in organic solar cells significantly limit the power conversion efficiencies (PCEs) of these devices, with the result that the current highest PCE values in single-junction organic photovoltaic remain smaller than for other solar cell technologies, such as crystalline silicon or perovskite solar cells. In particular, the nonradiative recombinations to the electronic ground state from the lowest-energy charge-transfer (CT) states at the donor–acceptor interfaces in the active layer of organic devices, are responsible for a significant part of the voltage losses. Here, to better comprehend the nonradiative voltage loss mechanisms, a fully quantum-mechanical rate formula is employed within the framework of time-dependent perturbation theory, combined with density functional theory. The objective is to uncover the specific contributions of intramolecular vibrations to the CT-state nonradiative recombinations in several model systems, which include small-molecule and polymer donors as well as fullerene and nonfullerene acceptors.The large open-circuit voltage losses in organic solar cells significantly limit the power conversion efficiencies (PCEs) of these devices. A major contribution to the voltage loss is the non-radiative recombination to the electronic ground states from the lowest-energy charge-transfer (CT) states at donor-acceptor interfaces. Here, we uncover the role of intramolecular vibrations in the CT-state non-radiative recombination.
      PubDate: 2017-12-18T05:44:06.167864-05:
      DOI: 10.1002/aenm.201702227
  • A Soft and Robust Spring Based Triboelectric Nanogenerator for Harvesting
    • Authors: Minyi Xu; Peihong Wang, Yi-Cheng Wang, Steven L. Zhang, Aurelia Chi Wang, Chunli Zhang, Zhengjun Wang, Xinxiang Pan, Zhong Lin Wang
      Abstract: Vibration is a common mechanical phenomenon and possesses mechanical energy in ambient environment, which can serve as a sustainable source of power for equipment and devices if it can be effectively collected. In the present work, a novel soft and robust triboelectric nanogenerator (TENG) made of a silicone rubber-spring helical structure with nanocomposite-based elastomeric electrodes is proposed. Such a spring based TENG (S-TENG) structure operates in the contact-separation mode upon vibrating and can effectively convert mechanical energy from ambient excitation into electrical energy. The two fundamental vibration modes resulting from the vertical and horizontal excitation are analyzed theoretically, numerically, and experimentally. Under the resonant states of the S-TENG, its peak power density is found to be 240 and 45 mW m−2 with an external load of 10 MΩ and an acceleration amplitude of 23 m s−2. Additionally, the dependence of the S-TENG's output signal on the ambient excitation can be used as a prime self-powered active vibration sensor that can be applied to monitor the acceleration and frequency of the ambient excitation. Therefore, the newly designed S-TENG has a great potential in harvesting arbitrary directional vibration energy and serving as a self-powered vibration sensor.A novel soft and robust triboelectric nanogenerator (TENG) made of a silicone rubber-spring helical structure with nanocomposite based elastomeric electrodes is designed. Such a spring based TENG structure operates in contact-separation mode upon vibrating and can effectively convert mechanical energy from arbitrary direction excitation into electrical energy. It can also serve as a self-powered sensor for vibration monitoring.
      PubDate: 2017-12-18T05:39:22.046592-05:
      DOI: 10.1002/aenm.201702432
  • Graphene Layers-Wrapped Fe/Fe5C2 Nanoparticles Supported on N-doped
           Graphene Nanosheets for Highly Efficient Oxygen Reduction
    • Authors: Enlai Hu; Xin-Yao Yu, Fang Chen, Yadan Wu, Yong Hu, Xiong Wen (David) Lou
      Abstract: Synthesis of highly efficient nonprecious metal electrocatalysts for the oxygen reduction reaction (ORR) superior to platinum (Pt) is still a big challenge. Herein, a new highly active ORR electrocatalyst is reported based on graphene layers-wrapped Fe/Fe5C2 nanoparticles supported on N-doped graphene nanosheets (GL-Fe/Fe5C2/NG) through simply annealing a mixture of bulk graphitic carbon nitride (g-C3N4) and ferrocene. An interesting exfoliation–denitrogen mechanism underlying the conversion of bulk g-C3N4 into N-doped graphene nanosheets is revealed. Owing to the high graphitic degree, optimum N-doping level and sufficient active sites from the graphene layers-wrapped Fe/Fe5C2 nanoparticles, the as-prepared GL-Fe/Fe5C2/NG electrocatalyst obtained at 800 °C exhibits outstanding ORR activity with a 20 mV more positive half-wave potential than the commercial Pt/C catalyst in 0.1 m KOH solution and a comparable onset potential of 0.98 V. This makes GL-Fe/Fe5C2/NG an outstanding electrocatalyst for ORR in alkaline solution.Graphene layers-wrapped Fe/Fe5C2 nanoparticles supported on N-doped graphene nanosheets (GL-Fe/Fe5C2/NG) are synthesized through simply annealing a mixture of bulk graphitic carbon nitride (g-C3N4) and ferrocene. Owing to the high graphitic degree, optimum N-doping level and sufficient active sites from the graphene layers-wrapped Fe/Fe5C2 nanoparticles, the as-prepared GL-Fe/Fe5C2/NG electrocatalyst exhibits outstanding oxygen reduction reaction activity.
      PubDate: 2017-12-18T05:27:51.197795-05:
      DOI: 10.1002/aenm.201702476
  • Atomically Thin Mesoporous In2O3–x/In2S3 Lateral Heterostructures
           Enabling Robust Broadband-Light Photo-Electrochemical Water Splitting
    • Authors: Jungang Hou; Shuyan Cao, Yiqing Sun, Yunzhen Wu, Fei Liang, Zheshuai Lin, Licheng Sun
      Abstract: Atomically thin 2D heterostructures have opened new realms in electronic and optoelectronic devices. Herein, 2D lateral heterostructures of mesoporous In2O3–x/In2S3 atomic layers are synthesized through the in situ oxidation of In2S3 atomic layers by an oxygen plasma-induced strategy. Based on experimental observations and theoretical calculations, the prolonged charge carrier lifetime and increased electron density reveal the efficient photoexcited carrier transport and separation in the In2O3–x/In2S3 layers by interfacial bonding at the atomic level. As expected, the synergistic structural and electronic modulations of the In2O3–x/In2S3 layers generate a photocurrent of 1.28 mA cm−2 at 1.23 V versus a reversible hydrogen electrode, nearly 21 and 79 times higher than those of the In2S3 atomic layers and bulk counterpart, respectively. Due to the large surface area, abundant active sites, broadband-light harvesting ability, and effective charge transport pathways, the In2O3–x/In2S3 layers build efficient pathways for photoexcited charge in the 2D semiconductive channels, expediting charge transport and kinetic processes and enhancing the robust broadband-light photo-electrochemical water splitting performance. This work paves new avenues for the exploration and design of atomically thin 2D lateral heterostructures toward robust photo-electrochemical applications and solar energy utilization.Atomically thin 2D mesoporous In2O3–x/In2S3 lateral heterostructures are synthesized through the in situ oxidation of In2S3 atomic layers. By virtue of large surface area, abundant active sites, broadband-light harvesting ability, and effective charge transport pathways, the In2O3–x/In2S3 heterostructures build efficient charge transport pathways in 2D semiconductive channels, expediting charge transport and kinetic processes and enhancing robust broadband-light photo-electrochemical water splitting performance.
      PubDate: 2017-12-18T02:47:48.729229-05:
      DOI: 10.1002/aenm.201701114
  • Multiple Cases of Efficient Nonfullerene Ternary Organic Solar Cells
           Enabled by an Effective Morphology Control Method
    • Authors: Kui Jiang; Guangye Zhang, Guofang Yang, Jianquan Zhang, Zhengke Li, Tingxuan Ma, Huawei Hu, Wei Ma, Harald Ade, He Yan
      Abstract: Ternary organic solar cells (OSCs) have attracted much research attention, as they can maintain the simplicity of the single-junction device architecture while broadening the absorption range of OSCs. However, one main challenge that limits the development of ternary OSCs is the difficulty in controlling the morphology of ternary OSCs. In this paper, an effective approach to control the morphology is presented that leads to multiple cases of efficient nonfullerene ternary OSCs with efficiencies of up to 11.2%. This approach is based on a donor polymer with strong temperature dependent aggregation properties processed from hot solutions without any solvent additives and a pair of small molecular acceptors (SMAs) that have similar surface tensions and thus low propensity to form discrete phases. Such a ternary blend exhibits a simplified bulk-heterojunction morphology that is similar to the morphology of previously reported binary blends. As a result, an almost linear relationship between VOC and film composition is observed for all nonfullerene ternary devices. Meanwhile, by carefully designing a control system with a large interfacial tension, a different phase separation and VOC dependence is demonstrated. This morphology control approach can be applicable to more material systems and accelerates the development of the ternary OSC field.Multiple cases of efficient nonfullerene ternary organic solar cells with efficiencies of up to 11.2% based on an effective morphology-control approach are presented. This approach is based on a donor polymer with strong temperature dependent aggregation and a pair of small molecular acceptors with similar surface tensions. Increased crystallinity of the acceptor phase is observed and discussed.
      PubDate: 2017-12-18T02:40:08.629161-05:
      DOI: 10.1002/aenm.201701370
  • Palladium Nanoparticles Anchored on Anatase Titanium Dioxide-Black
           Phosphorus Hybrids with Heterointerfaces: Highly Electroactive and Durable
           Catalysts for Ethanol Electrooxidation
    • Authors: Tong Wu; Jinchen Fan, Qiaoxia Li, Penghui Shi, Qunjie Xu, Yulin Min
      Abstract: Designing high-performance palladium (Pd) supports with enhanced ethanol oxidation reaction (EOR) activity has consistently been a challenge. Here, a novel anatase titanium dioxide nanosheets-black phosphorus (ATN-BP) hybrid is fabricated as a support for Pd nanoparticles used in the EOR. The direct ball-milling of BP nanoflakes and ATN under argon protection lead to the formation of ATN-BP hybrids with BP nanoflakes interconnected by cataclastic ATN with POTi bonds. The structure of ATN-BP not only is beneficial for improving the electrolyte penetration and electron transportation but also has a strong influence on the stripping of reactive intermediates through the synergistic interaction between Pd and ATN-BP. The results demonstrate that the Pd/ATN-BP hybrids with heterointerfaces of Pd, BP, and ATN exhibit ultrahigh electroactivity and durability. In the EOR, the Pd/ATN-BP catalyst can achieve an electrochemically active surface area of ≈462.1 m2 gPd−1 and a mass peak current density of 5023.8 mA mgPd−1, which are 11.67 and 6.87 times greater, respectively, than those of commercial Pd/C. The Pd/ATN-BP catalysts also show remarkable stability with a retention rate of the peak current density of ≈30.6% after a durability test of 3600 s.Ultrahigh-performance ethanol electrooxidation: The combination of anatase titanium dioxide nanosheets (ATN) with black phosphorus (BP) is used to support palladium (Pd) nanoparticles. The Pd/ATN-BP catalyst exhibits super high electrochemical active surface area (462.1 m2 gPd−1) and mass peak current density (5023.8 mA mgPd−1) for ethanol electrooxidation, which are 11.67 and 6.87 times higher, respectively, than those of commercial Pd/Carbon.
      PubDate: 2017-10-04T03:07:44.698365-05:
      DOI: 10.1002/aenm.201701799
  • Molecular Interlayers in Hybrid Perovskite Solar Cells
    • Authors: Wentao Deng; Xinxing Liang, Peter S. Kubiak, Petra J. Cameron
      Abstract: Organic–inorganic hybrid perovskite solar cells (PSC) are promising third-generation solar cells. They exhibit good power conversion efficiencies and in principle they can be fabricated with lower energy consumption than many more established technologies. To improve the efficiency and long-term stability of PSC, organic molecules are frequently used as “interlayers.” Interlayers are thin layers or monolayers of organic molecules that modify a specific interface in the solar cell. Here, the latest progress in the use of interlayers to optimize the performance of PSC is reviewed. Where appropriate interesting examples from the field of organic photovoltaics (OPV) are also presented as there are many similarities in the types of interlayers that are used in PSC and OPV. The review is organized into three parts. The first part focuses on why organic molecule interlayers improve the performance of the solar cells. The second section discusses commonly used molecular interlayers. In the last part, different approaches to make thin and uniform interlayers are discussed.Small molecules are increasingly being used as interlayers in perovskite solar cells to modify band energy offsets at an interface, to improve the morphology of active layers, and to enhance the long-term stability of the devices. This article reviews recent advances in the use of molecular interlayers in perovskite cells and introduces relevant examples from the field of organic solar cells.
      PubDate: 2017-09-18T11:44:15.351604-05:
      DOI: 10.1002/aenm.201701544
  • Single-Atom Catalysts: Emerging Multifunctional Materials in Heterogeneous
    • Authors: Huabin Zhang; Guigao Liu, Li Shi, Jinhua Ye
      Abstract: Supported metal nanoparticles are the most widely investigated heterogeneous catalysts in catalysis community. The size of metal nanostructures is an important parameter in influencing the activity of constructed catalysts. Especially, as coordination unsaturated metal atoms always work as the catalytically active centers, decreasing the particle size of the catalyst can greatly boost the specific activity per metal atom. Single-atom catalysts (SACs), containing single metal atoms anchored on supports, represent the utmost utilization of metallic catalysts and thus maximize the usage efficiency of metal atom. However, with the decreasing of particle size, the surface free energy increases obviously, and tends to aggregate into clusters or particles. Selection of an appropriate support is necessary to interact with isolated atoms strongly, and thus prevents the movement and aggregation of isolated atoms, creating stable, finely dispersed active sites. Furthermore, with uniform single-atom dispersion and well-defined configuration, SACs afford great space for optimizing high selectivity and activity. In this review, a detailed discussion of preparing, characterizing, and catalytically testing within this family is provided, including the theoretical understanding of key aspects of SACs materials. The main advantages of SACs as catalysts and the challenges faced for further improving catalytic performance are also highlighted.In this review, a detailed discussion of preparing, characterizing, and catalytically testing within this family is provided, including the theoretical understanding of key aspects of single atom catalysts (SACs) materials. The main advantages of SACs as catalysts and the challenges faced for further improving catalytic performance are also highlighted.
      PubDate: 2017-09-18T07:39:15.413712-05:
      DOI: 10.1002/aenm.201701343
  • Single-Crystalline Nanomesh Tantalum Nitride Photocatalyst with Improved
           Hydrogen-Evolving Performance
    • Authors: Mu Xiao; Bin Luo, Miaoqiang Lyu, Songcan Wang, Lianzhou Wang
      Abstract: Tantalum nitride (Ta3N5) with a suitable bandgap (≈2 eV) is regarded as one of the most promising photocatalysts for efficient solar energy harvesting and conversion. However, Ta3N5 suffers from low hydrogen production activity due to the low carrier mobility and fast carrier recombination. Thus, the design of Ta3N5 nanostructures to facilitate charge carrier transport and improve photocatalytic performance remains a challenge. This study reports a new type of ultrathin (≈2 nm) Ta3N5 nanomesh with high specific surface area (284.6 m2 g−1) and excellent crystallinity by an innovative bottom-up graphene oxide templated strategy. The resulting Ta3N5 nanomeshes demonstrate drastically improved electron transport ability and prolonged lifetime of charge carriers, due to the nature of high surface area and excellent crystallinity. As a result, when used as photocatalysts, the Ta3N5 nanomeshes exhibit a greater than tenfold improvement in solar hydrogen production compared to bulk counterparts. This work provides an effective and generic strategy for designing 2D ultrathin nanomesh structures for nonlayered materials with improved catalytic activity.Novel single-crystalline Ta3N5 nanomeshes with thicknesses of approximately 2 nm are developed using a bottom-up strategy. The unique architecture has a high specific surface area, improved electron transport ability, and prolonged life time of photogenerated charge carriers. It therefore yields tenfold improvement in the hydrogen evolution rate when compared to its bulk counterpart under simulated sunlight.
      PubDate: 2017-09-14T11:43:50.223251-05:
      DOI: 10.1002/aenm.201701605
  • Surface-Modified Porous Carbon Nitride Composites as Highly Efficient
           Electrocatalyst for Zn-Air Batteries
    • Authors: Wenhan Niu; Zhao Li, Kyle Marcus, Le Zhou, Yilun Li, Ruquan Ye, Kun Liang, Yang Yang
      Abstract: Porous carbon nitride (PCN) composites are fabricated using a top-down strategy, followed by additions of graphene and CoSx nanoparticles. This subsequently enhances conductivity and catalytic activity of PCN (abbreviated as CoSx@PCN/rGO) and is achieved by one-step sulfuration of PCN/graphene oxides (GO) composite materials. As a result, the as-prepared CoSx@PCN/rGO catalysts display excellent activity and stability toward both oxygen evolution and reduction reactions, surpassing electrocatalytic performance shown by state-of-the-art Pt, RuO2 and other carbon nitrides. Remarkably, the CoSx@PCN/rGO bifunctional activity allows for applications in zinc-air batteries, which show better rechargeability than Pt/C. The enhanced catalytic performance of CoSx@PCN/rGO can primarily be attributed to the highly porous morphology and sufficiently exposed active sites that are favorable for electrocatalytic reactions.A novel porous g-C3N4-based electrocatalyst, with outstanding electrocatalytic performance for oxygen evolution and oxygen reduction reactions, is developed using a template-free approach. A low potential gap of 0.79 V and long-term stability over 43.8 h are achieved in Zn-air battery testing, which are superior to benchmarking Pt and RuO2-based electrocatalysts.
      PubDate: 2017-09-14T01:05:02.675619-05:
      DOI: 10.1002/aenm.201701642
  • 8.0% Efficient All-Polymer Solar Cells with High Photovoltage of 1.1 V and
           Internal Quantum Efficiency near Unity
    • Authors: Xiaofeng Xu; Zhaojun Li, Wei Zhang, Xiangyi Meng, Xianshao Zou, Dario Di Carlo Rasi, Wei Ma, Arkady Yartsev, Mats R. Andersson, René A. J. Janssen, Ergang Wang
      Abstract: In very recent years, growing efforts have been devoted to the development of all-polymer solar cells (all-PSCs). One of the advantages of all-PSCs over the fullerene-based PSCs is the versatile design of both donor and acceptor polymers which allows the optimization of energy levels to maximize the open-circuit voltage (Voc). However, there is no successful example of all-PSCs with both high Voc over 1 V and high power conversion efficiency (PCE) up to 8% reported so far. In this work, a combination of a donor polymer poly[4,8-bis(5-(2-octylthio)thiophen-2-yl)benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl-alt-(5-(2-ethylhexyl)-4H-thieno[3,4-c]pyrrole-4,6(5H)-dione)-1,3-diyl] (PBDTS-TPD) with a low-lying highest occupied molecular orbital level and an acceptor polymer poly[[N,N′-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-thiophene-2,5-diyl] (PNDI-T) with a high-lying lowest unoccupied molecular orbital level is used, realizing high-performance all-PSCs with simultaneously high Voc of 1.1 V and high PCE of 8.0%, and surpassing the performance of the corresponding PC71BM-based PSCs. The PBDTS-TPD:PNDI-T all-PSCs achieve a maximum internal quantum efficiency of 95% at 450 nm, which reveals that almost all the absorbed photons can be converted into free charges and collected by electrodes. This work demonstrates the advantages of all-PSCs by incorporating proper donor and acceptor polymers to boost both Voc and PCEs.High-performance all-polymer solar cells with high Voc of 1.1 V and PCE of 8.0% are realized by incorporating a pair of the donor polymer poly[4,8-bis(5-(2-octylthio)thiophen-2-yl)benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl-alt-(5-(2-ethylhexyl)-4H-thieno[3,4-c]pyrrole-4,6(5H)-dione)-1,3-diyl] and acceptor polymer poly[[N,N′-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-thiophene-2,5-diyl]. The simultaneously high Voc and power conversion efficiency stem from the low photon energy loss and high internal quantum efficiency near unity.
      PubDate: 2017-09-11T10:39:39.883899-05:
      DOI: 10.1002/aenm.201700908
  • Highly Durable Platinum Single-Atom Alloy Catalyst for Electrochemical
    • Authors: Jiwhan Kim; Chi-Woo Roh, Suman Kalyan Sahoo, Sungeun Yang, Junemin Bae, Jeong Woo Han, Hyunjoo Lee
      Abstract: Single atomic Pt catalyst can offer efficient utilization of the expensive platinum and provide unique selectivity because it lacks ensemble sites. However, designing such a catalyst with high Pt loading and good durability is very challenging. Here, single atomic Pt catalyst supported on antimony-doped tin oxide (Pt1/ATO) is synthesized by conventional incipient wetness impregnation, with up to 8 wt% Pt. The single atomic Pt structure is confirmed by high-angle annular dark field scanning tunneling electron microscopy images and extended X-ray absorption fine structure analysis results. Density functional theory calculations show that replacing Sb sites with Pt atoms in the bulk phase or at the surface of SbSn or ATO is energetically favorable. The Pt1/ATO shows superior activity and durability for formic acid oxidation reaction, compared to a commercial Pt/C catalyst. The single atomic Pt structure is retained even after a harsh durability test, which is performed by repeating cyclic voltammetry in the range of 0.05–1.4 V for 1800 cycles. A full cell is fabricated for direct formic acid fuel cell using the Pt1/ATO as an anode catalyst, and an order of magnitude higher cell power is obtained compared to the Pt/C.Platinum single-atom alloy is prepared on an antimony-doped tin oxide support (Pt1/ATO) and used for electrochemical formic acid oxidation with high activity and durability. The single atomic nature of Pt is retained even after the durability test performed by repeating cyclic voltammetry 1800 times in 0.05–1.4 V.
      PubDate: 2017-09-11T01:32:59.90275-05:0
      DOI: 10.1002/aenm.201701476
  • 3D Porous Cu–Zn Alloys as Alternative Anode Materials for Li-Ion
           Batteries with Superior Low T Performance
    • Authors: Alberto Varzi; Luca Mattarozzi, Sandro Cattarin, Paolo Guerriero, Stefano Passerini
      Abstract: Zinc is recently gaining interest in the battery community as potential alternative anode material, because of its large natural abundance and potentially larger volumetric density than graphite. Nevertheless, pure Zn anodes have shown so far very poor cycling performance. Here, the electrochemical performance of Zn-rich porous Cu–Zn alloys electrodeposited by an environmentally friendly (aqueous) dynamic hydrogen bubble template method is reported. The lithiation/delithiation mechanism is studied in detail by both in situ and ex situ X-ray diffraction, indicating the reversible displacement of Zn from the Cu–Zn alloy upon reaction with Li. The influence of the alloy composition on the performance of carbon- and binder-free electrodes is also investigated. The optimal Cu:Zn atomic ratio is found to be 18:82, which provides impressive rate capability up to 10 A g−1 (≈30C), and promising capacity retention upon more than 500 cycles. The high electronic conductivity provided by Cu, and the porous electrode morphology also enable superior lithium storage capability at low temperature. Cu18Zn82 can indeed steadily deliver ≈200 mAh g−1 at −20 °C, whereas an analogous commercial graphite electrode rapidly fades to only 12 mAh g−1.Zinc-rich porous CuZn alloys are studied as alternative anodes for lithium-ion batteries. The carbon- and binder-free electrodes, produced by environmentally friendly electrodeposition in aqueous media, display promising cycling stability compared to pure Zn (more than 500 cycles) and, most interestingly, superior performance at low temperatures with ≈200 mAh g−1 delivered at −20 °C.
      PubDate: 2017-09-11T01:27:08.757753-05:
      DOI: 10.1002/aenm.201701706
  • Unique Role of Refractory Ta Alloying in Enhancing the Figure of Merit of
           NbFeSb Thermoelectric Materials
    • Authors: Junjie Yu; Chenguang Fu, Yintu Liu, Kaiyang Xia, Umut Aydemir, Thomas C. Chasapis, G. Jeffrey Snyder, Xinbing Zhao, Tiejun Zhu
      Abstract: NbFeSb-based half-Heusler alloys have been recently identified as promising high-temperature thermoelectric materials with a figure of merit zT > 1, but their thermal conductivity is still relatively high. Alloying Ta at the Nb site would be highly desirable because the large mass fluctuation between them could effectively scatter phonons and reduce the lattice thermal conductivity. However, practically it is a great challenge due to the high melting point of refractory Ta. Here, the successful synthesis of Ta-alloyed (Nb1−xTax)0.8Ti0.2FeSb (x = 0 – 0.4) solid solutions with significantly reduced thermal conductivity by levitation melting is reported. Because of the similar atomic sizes and chemistry of Nb and Ta, the solid solutions exhibit almost unaltered electrical properties. As a result, an overall zT enhancement from 300 to 1200 K is realized in the single-phase Ta-alloyed solid solutions, and the compounds with x = 0.36 and 0.4 reach a maximum zT of 1.6 at 1200 K. This work also highlights that the isoelectronic substitution by atoms with similar size and chemical nature but large mass difference should reduce the lattice thermal conductivity but maintain good electrical properties in thermoelectric materials, which can be a guide for optimizing the figure of merit by alloying.The successful synthesis of single-phase Ta-alloyed (Nb1−xTax)0.8Ti0.2FeSb (x = 0 – 0.4) thermoelectric materials by levitation melting is reported. Refractory Ta alloying dramatically reduces the thermal conductivity but maintains the good electrical properties due to the similar chemical nature between Ta and Nb, resulting in a high figure of merit, zT, of 1.6.
      PubDate: 2017-09-07T11:26:56.99545-05:0
      DOI: 10.1002/aenm.201701313
  • Laser Porosificated Silicon Anodes for Lithium Ion Batteries
    • Authors: Christian Sämann; Katerina Kelesiadou, Seyedeh Sheida Hosseinioun, Mario Wachtler, Jürgen R. Köhler, Kai Peter Birke, Markus B. Schubert, Jürgen H. Werner
      Abstract: This study presents the first laser porosificated silicon anode for lithium-ion batteries. The pulsed laser induced pore creation improves the cycling stability of the d = 210 nm thick sputtered thin film anodes compared to plain Si. Galvanostatic cycling with a charge capacity limited to C = 932 mAh g−1 and a 2C current rate shows a stable cycling for more than N = 600 cycles. After N = 3000 cycles the laser porosificated and crystallized Si has a remaining capacity of C3000 > 120 mAh g−1. Postmortem scanning electron microscopy images after N = 3000 cycles prove that the laser porosification reduces cracks in the active layer.In lithium batteries, silicon anodes expand up to 250% in volume during lithium insertion, which mechanically damages the silicon. The morphology of silicon must be adjusted for this volume expansion. Laser porosification uses single laser pulses to produce porous structured silicon films, which improves the cycling stability of the silicon anodes.
      PubDate: 2017-09-05T12:01:11.643255-05:
      DOI: 10.1002/aenm.201701705
  • An Efficient and Earth-Abundant Oxygen-Evolving Electrocatalyst Based on
           Amorphous Metal Borides
    • Authors: Jean Marie Vianney Nsanzimana; Yuecheng Peng, Yang Yang Xu, Larissa Thia, Cheng Wang, Bao Yu Xia, Xin Wang
      Abstract: Cost-effective and efficient oxygen-evolving electrocatalysts are urgently required for energy storage and conversion technologies. In this work, an amorphous trimetallic boride nanocatalyst (Fe–Co–2.3Ni–B) prepared by a simple approach is reported as a highly efficient oxygen evolution reaction electrocatalyst. It exhibits an overpotential (η) of 274 mV to deliver a geometric current density (jgeo) of 10 mA cm−2, a small Tafel slope of 38 mV dec−1, and excellent long-term durability at a mass loading of 0.3 mg cm−2. The impressive electrocatalytic performance originates from the unique amorphous multimetal–metalloid complex nanostructure. From application's point of view, this work holds great promise as this process is simple and allows for large-scale production of cheap, yet efficient, material.Amorphous trimetallic boride demonstrates impressive electrocatalytic oxygen evolution activity, which originates from the tuned electronic properties of the constituent elements. Such an earth-abundant boride electrocatalyst holds great promise for practical applications in water electrosplitting devices as the synthesis process is simple and allows for large-scale production of cheap, yet efficient, material.
      PubDate: 2017-09-04T07:31:49.375045-05:
      DOI: 10.1002/aenm.201701475
  • Single-Atom to Single-Atom Grafting of Pt1 onto FeN4 Center: Pt1@FeNC
           Multifunctional Electrocatalyst with Significantly Enhanced Properties
    • Authors: Xiaojun Zeng; Jianglan Shui, Xiaofang Liu, Qingtao Liu, Yongcheng Li, Jiaxiang Shang, Lirong Zheng, Ronghai Yu
      Abstract: Nonprecious metal catalysts (NPMCs) FeNC are promising alternatives to noble metal Pt as the oxygen reduction reaction (ORR) catalysts for proton-exchange-membrane fuel cells. Herein, a new modulation strategy is reported to the active moiety FeN4 via a precise “single-atom to single-atom” grafting of a Pt atom onto the Fe center through a bridging oxygen molecule, creating a new active moiety of Pt1O2Fe1N4. The modulated FeNC exhibits remarkably improved ORR stabilities in acidic media. Moreover, it shows unexpectedly high catalytic activities toward oxygen evolution reaction (OER) and hydrogen evolution reaction (HER), with overpotentials of 310 mV for OER in alkaline solution and 60 mV for HER in acidic media at a current density of 10 mA cm−2, outperforming the benchmark RuO2 and comparable with Pt/C(20%), respectively. The enhanced multifunctional electrocatalytic properties are associated with the newly constructed active moiety Pt1O2Fe1N4, which protects Fe sites from harmful species. Density functional theory calculations reveal the synergy in the new active moiety, which promotes the proton adsorption and reduction kinetics. In addition, the grafted Pt1O2 dangling bonds may boost the OER activity. This study paves a new way to improve and extend NPMCs electrocatalytic properties through a precisely single-atom to single-atom grafting strategy.Grafting Pt single-atoms onto FeN4 moieties of FeNC electrocatalyst results in a new active moiety Pt1O2Fe1N4, which exhibits extended electrocatalytic properties including improved oxygen reduction reaction (ORR) stability in acidic media, unexpectedly high OER and HER activities. The protection of Pt1O2 to Fe atom, synergy, and dangling bonds in the new active moieties are responsible for the much enhanced multifunctional electrocatalytic properties.
      PubDate: 2017-09-04T07:31:19.820469-05:
      DOI: 10.1002/aenm.201701345
  • Popcorn Inspired Porous Macrocellular Carbon: Rapid Puffing Fabrication
           from Rice and Its Applications in Lithium–Sulfur Batteries
    • Authors: Yu Zhong; Xinhui Xia, Shengjue Deng, Jiye Zhan, Ruyi Fang, Yang Xia, Xiuli Wang, Qiang Zhang, Jiangping Tu
      Abstract: The advancement of electrochemical energy storage is closely bound up with the breakthrough of controllable fabrication of energy materials. Inspired by a popcorn fabrication from corn raw, herein a unique porous macrocellular carbon composed of cross-linked nano/microsheets by a powerful puffing of rice precursor is described. The rice is directly puffed with a volume enlargement of ≈20 times when it is instantaneously released from a sealed environment with a high pressure of 1.0 MPa at 200 °C. Interestingly, when metal (e.g., Ni) nanoparticles are embedded in the puffed rice derived carbon (PRC), high-quality PRC/metal composites are achieved with attractive properties of a high electrical conductivity of ≈7.2 × 104 S m−1, a large porosity of 85.1%, and a surface area of 1492.2 m2 g−1. The PRC/Ni are employed as a host in lithium–sulfur batteries. The designed PRC/Ni/S electrode exhibits a high reversible capacity of 1257.2 mA h g−1 at 0.2 C, a prolonged cycle life (821 mA h g−1 after 500 cycles), and enhanced rate capability, much better than other counterparts (PRC/S and rGO/S). The excellent properties are attributed to the advantages of PRC/Ni network with a high electrical conductivity, strong adsorption/blocking ability for polysulfides, and interconnected porous framework.A unique porous microcellular carbon composed of cross-linked nano/microsheets created by a powerful puffing of a rice precursor is described. Because of the advantages of the puffed-rice-derived carbon/Ni network with a high electrical conductivity and strong adsorption/blocking ability for polysulfides, the microcellular carbon-based electrode exhibits high sulfur utilization, long cycling life, and high rate performance in a working lithium–sulfur battery.
      PubDate: 2017-09-01T14:48:16.371478-05:
      DOI: 10.1002/aenm.201701110
  • Bismuth Tantalum Oxyhalogen: A Promising Candidate Photocatalyst for Solar
           Water Splitting
    • Authors: Xiaoping Tao; Yue Zhao, Linchao Mu, Shengyang Wang, Rengui Li, Can Li
      Abstract: As wide range of light absorption and suitable redox potentials are prerequisites for photocatalytic water splitting, exploring new semiconductor-based materials with proper band structures for water splitting still calls for longstanding efforts. In this work, a series of photocatalysts, bismuth tantalum oxyhalide, Bi4TaO8X (X = Cl, Br), with valence band and conduction band positions at ≈−0.70 and ≈1.80 eV versus the reversible hydrogen electrode (RHE), respectively, are found to be capable for both water oxidation and reduction under visible light irradiation. Using flux synthetic methods, Bi4TaO8X (X = Cl, Br) with microplatelet morphology can be successfully prepared. The photocatalyst based on these materials shows an apparent quantum efficiency as high as 20% at 420 nm for water oxidation. In addition, a Z-scheme system coupling Bi4TaO8Br with Ru/SrTiO3:Rh is successfully achieved for overall water splitting with a stoichiometric ratio of H2 and O2 evolutions. This work demonstrates a new series of semiconductors Bi4TaO8X (X = Cl, Br) with the promising application in the field of solar energy utilization.A series of photocatalysts, bismuth tantalum oxyhalides, Bi4TaO8X (X = Cl, Br), with the energy band gaps of around 2.5 eV, are explored and found to be capable of both water oxidation and reduction under visible light irradiation. Notably, an apparent quantum efficiency as high as 20% (at 420 nm) for water oxidation is achieved.
      PubDate: 2017-09-01T14:45:23.990603-05:
      DOI: 10.1002/aenm.201701392
  • Metal–Organic Framework Templated Porous Carbon-Metal Oxide/Reduced
           Graphene Oxide as Superior Support of Bimetallic Nanoparticles for
           Efficient Hydrogen Generation from Formic Acid
    • Authors: Fu-Zhan Song; Qi-Long Zhu, Xinchun Yang, Wen-Wen Zhan, Pradip Pachfule, Nobuko Tsumori, Qiang Xu
      Abstract: Ultrafine PdAg nanoparticles (NPs) are successfully immobilized on zirconia/porous carbon/reduced graphene oxide (ZrO2/C/rGO) nanocomposite derived from metal organic framework/graphene oxide. Monodispersed PdAg NPs (diameter ≤2.5 nm) can be facilely anchored on the ZrO2/C/rGO and the aggregation of metal NPs can be avoided utmostly. By virtue of the synergistic effect between metal NPs and support, the resulting PdAg@ZrO2/C/rGO exhibits excellent activity (turnover frequency, 4500 h−1 at 333 K) for the dehydrogenation of formic acid. As an effective strategy, it provides an opportunity to immobilize ultrafine metal NPs on metal oxide/porous carbon/reduced graphene oxide, which has tremendous application prospects in various catalytic fields.A superior support, namely ZrO2/C/rGO derived from metal–organic framework/graphene oxide, to immobilize ultrafine PdAg nanoparticles (NPs) (diameter ≤ 2.5 nm) is reported. By virtue of the synergistic effect between metal NPs and support, the resulting PdAg@ZrO2/C/rGO nanocatalyst shows extremely high catalytic performance (turnover frequency, 4500 h−1) for the dehydrogenation of formic acid.
      PubDate: 2017-09-01T14:45:03.491216-05:
      DOI: 10.1002/aenm.201701416
  • Fully Solution-Processed TCO-Free Semitransparent Perovskite Solar Cells
           for Tandem and Flexible Applications
    • Authors: Yaokang Zhang; Zhongwei Wu, Peng Li, Luis K. Ono, Yabing Qi, Jixiang Zhou, Hui Shen, Charles Surya, Zijian Zheng
      Abstract: Semitransparent perovskite solar cells (st-PSCs) have received remarkable interest in recent years because of their great potential in applications for solar window, tandem solar cells, and flexible photovoltaics. However, all reported st-PSCs require expensive transparent conducting oxides (TCOs) or metal-based thin films made by vacuum deposition, which is not cost effective for large-scale fabrication: the cost of TCOs is estimated to occupy ≈75% of the manufacturing cost of PSCs. To address this critical challenge, this study reports a low-temperature and vacuum-free strategy for the fabrication of highly efficient TCO-free st-PSCs. The TCO-free st-PSC on glass exhibits 13.9% power conversion efficiency (PCE), and the four-terminal tandem cell made with the st-PSC top cell and c-Si bottom cell shows an overall PCE of 19.2%. Due to the low processing temperature, the fabrication of flexible st-PSCs is demonstrated on polyethylene terephthalate and polyimide, which show excellent stability under repeated bending or even crumbing.Fully solution-processed transparent conducting oxide-free semitransparent perovskite solar cells are reported to allow low-cost fabrication of highly efficient tandem solar cells and flexible solar cells. Nitric acid annealed poly(3,4-ethylenedioxythiophene): polystyrene sulfonate is incorporated in the fabrication process to realize high-throughput printing of highly conductive transparent electrodes.
      PubDate: 2017-09-01T14:43:07.351491-05:
      DOI: 10.1002/aenm.201701569
  • Understanding Film Formation Morphology and Orientation in High Member 2D
           Ruddlesden–Popper Perovskites for High-Efficiency Solar Cells
    • Authors: Chan Myae Myae Soe; Wanyi Nie, Constantinos C. Stoumpos, Hsinhan Tsai, Jean-Christophe Blancon, Fangze Liu, Jacky Even, Tobin J. Marks, Aditya D. Mohite, Mercouri G. Kanatzidis
      Abstract: 2D Ruddlesden–Popper (RP) perovskites have recently emerged as promising candidates for hybrid perovskite photovoltaic cells, realizing power-conversion efficiencies (PCEs) of over 10% with technologically relevant stability. To achieve solar cell performance comparable to the state-of-the-art 3D perovskite cells, it is highly desirable to increase the conductivity and lower the optical bandgap for enhanced near-IR region absorption by increasing the perovskite slab thickness. Here, the use of the 2D higher member (n = 5) RP perovskite (n-butyl-NH3)2(MeNH3)4Pb5I16 in depositing highly oriented thin films from dimethylformamide/dimethylsulfoxide mixtures using the hot-casting method is reported. In addition, they exhibit superior environmental stability over thin films of their 3D counterpart. These films are assembled into high-efficiency solar cells with an open-circuit voltage of ≈1 V and PCE of up to 10%. This is achieved by fine-tuning the solvent ratio, crystal growth orientation, and grain size in the thin films. The enhanced performance of the optimized devices is ascribed to the growth of micrometer-sized grains as opposed to more typically obtained nanometer grain size and highly crystalline, densely packed microstructures with the majority of the inorganic slabs preferentially aligned out of plane to the substrate, as confirmed by X-ray diffraction and grazing-incidence wide-angle X-ray scattering mapping.Controllable tuning of the thin film properties of high-n member layered Ruddlesden–Popper perovskites, BA2MA4Pb5I16, is achieved via a hot-casting method using dimethylformamide (DMF)/dimethylsulfoxide (DMSO) processing solvent. Unlike the polycrystalline films grown from DMF, the optimized 3:1 DMF:DMSO films are essentially single-crystalline with regularly stacked inorganic slabs, and deliver solar cell power conversion efficiencies up to 10%.
      PubDate: 2017-09-01T00:56:26.771824-05:
      DOI: 10.1002/aenm.201700979
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