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  Subjects -> ENGINEERING (Total: 1953 journals)
    - CHEMICAL ENGINEERING (153 journals)
    - CIVIL ENGINEERING (148 journals)
    - ELECTRICAL ENGINEERING (81 journals)
    - ENGINEERING (1110 journals)
    - ENGINEERING MECHANICS AND MATERIALS (290 journals)
    - HYDRAULIC ENGINEERING (45 journals)
    - INDUSTRIAL ENGINEERING (52 journals)
    - MECHANICAL ENGINEERING (74 journals)

ENGINEERING (1110 journals)            First | 2 3 4 5 6 7 8 9 | Last

International Journal of Mathematical Education in Science and Technology     Hybrid Journal   (Followers: 6)
International Journal of Mathematics in Operational Research     Hybrid Journal   (Followers: 1)
International Journal of Medical Engineering and Informatics     Hybrid Journal   (Followers: 5)
International Journal of Micro Air Vehicles     Full-text available via subscription   (Followers: 3)
International Journal of Microwave and Wireless Technologies     Hybrid Journal   (Followers: 1)
International Journal of Microwave Science and Technology     Open Access   (Followers: 2)
International Journal of Mobile Network Design and Innovation     Hybrid Journal   (Followers: 3)
International Journal of Multiphase Flow     Hybrid Journal   (Followers: 2)
International Journal of Nanomanufacturing     Hybrid Journal   (Followers: 1)
International Journal of Nanoscience     Hybrid Journal   (Followers: 1)
International Journal of Nanotechnology     Hybrid Journal   (Followers: 5)
International Journal of Navigation and Observation     Open Access   (Followers: 5)
International Journal of Network Management     Hybrid Journal  
International Journal of Nonlinear Sciences and Numerical Simulation     Full-text available via subscription   (Followers: 1)
International Journal of Numerical Methods for Heat & Fluid Flow     Hybrid Journal   (Followers: 7)
International Journal of Optics     Open Access   (Followers: 1)
International Journal of Organisational Design and Engineering     Hybrid Journal   (Followers: 8)
International Journal of Pattern Recognition and Artificial Intelligence     Hybrid Journal   (Followers: 6)
International Journal of Pavement Engineering     Hybrid Journal   (Followers: 2)
International Journal of Physical Modelling in Geotechnics     Hybrid Journal   (Followers: 3)
International Journal of Plasticity     Hybrid Journal   (Followers: 6)
International Journal of Plastics Technology     Hybrid Journal  
International Journal of Polymer Analysis and Characterization     Hybrid Journal   (Followers: 3)
International Journal of Polymer Science     Open Access   (Followers: 16)
International Journal of Precision Engineering and Manufacturing     Hybrid Journal   (Followers: 6)
International Journal of Precision Technology     Hybrid Journal  
International Journal of Pressure Vessels and Piping     Hybrid Journal   (Followers: 2)
International Journal of Production Economics     Hybrid Journal   (Followers: 10)
International Journal of Quality and Innovation     Hybrid Journal   (Followers: 2)
International Journal of Quality Engineering and Technology     Hybrid Journal   (Followers: 2)
International Journal of Quantum Information     Hybrid Journal  
International Journal of Rapid Manufacturing     Hybrid Journal   (Followers: 2)
International Journal of Reliability, Quality and Safety Engineering     Hybrid Journal   (Followers: 4)
International Journal of Renewable Energy Technology     Hybrid Journal   (Followers: 7)
International Journal of Robust and Nonlinear Control     Hybrid Journal   (Followers: 2)
International Journal of Science Engineering and Advance Technology     Open Access  
International Journal of Sediment Research     Full-text available via subscription   (Followers: 1)
International Journal of Self-Propagating High-Temperature Synthesis     Hybrid Journal   (Followers: 2)
International Journal of Signal and Imaging Systems Engineering     Hybrid Journal  
International Journal of Six Sigma and Competitive Advantage     Hybrid Journal  
International Journal of Social Robotics     Hybrid Journal   (Followers: 1)
International Journal of Software Engineering and Knowledge Engineering     Hybrid Journal   (Followers: 1)
International Journal of Space Science and Engineering     Hybrid Journal   (Followers: 2)
International Journal of Speech Technology     Hybrid Journal   (Followers: 3)
International Journal of Spray and Combustion Dynamics     Full-text available via subscription   (Followers: 5)
International Journal of Surface Engineering and Interdisciplinary Materials Science     Full-text available via subscription   (Followers: 1)
International Journal of Surface Science and Engineering     Hybrid Journal   (Followers: 7)
International Journal of Sustainable Engineering     Hybrid Journal   (Followers: 7)
International Journal of Sustainable Manufacturing     Hybrid Journal   (Followers: 4)
International Journal of Systems Assurance Engineering and Management     Hybrid Journal  
International Journal of Systems, Control and Communications     Hybrid Journal   (Followers: 2)
International Journal of Technology Management and Sustainable Development     Hybrid Journal   (Followers: 1)
International Journal of Technology Policy and Law     Hybrid Journal   (Followers: 4)
International Journal of Telemedicine and Applications     Open Access   (Followers: 2)
International Journal of Thermal Sciences     Hybrid Journal   (Followers: 4)
International Journal of Thermodynamics     Open Access   (Followers: 1)
International Journal of Turbo & Jet-Engines     Full-text available via subscription  
International Journal of Ultra Wideband Communications and Systems     Hybrid Journal  
International Journal of Vehicle Autonomous Systems     Hybrid Journal   (Followers: 1)
International Journal of Vehicle Design     Hybrid Journal   (Followers: 6)
International Journal of Vehicle Information and Communication Systems     Hybrid Journal   (Followers: 2)
International Journal of Vehicle Noise and Vibration     Hybrid Journal   (Followers: 3)
International Journal of Vehicle Safety     Hybrid Journal   (Followers: 4)
International Journal of Vehicular Technology     Open Access   (Followers: 2)
International Journal of Virtual Technology and Multimedia     Hybrid Journal   (Followers: 4)
International Journal of Wavelets, Multiresolution and Information Processing     Hybrid Journal  
International Journal on Artificial Intelligence Tools     Hybrid Journal   (Followers: 4)
International Nano Letters     Open Access   (Followers: 6)
International Review of Applied Sciences and Engineering     Full-text available via subscription  
Inverse Problems in Science and Engineering     Hybrid Journal   (Followers: 2)
Ionics     Hybrid Journal  
IPTEK The Journal for Technology and Science     Open Access  
IRBM News     Full-text available via subscription  
Irrigation and Drainage Systems     Hybrid Journal  
ISA Transactions     Full-text available via subscription   (Followers: 1)
ISRN - International Scholarly Research Notices     Open Access   (Followers: 69)
ISRN Nanotechnology     Open Access  
ISRN Signal Processing     Open Access  
ISRN Thermodynamics     Open Access  
IT Professional     Full-text available via subscription   (Followers: 2)
Journal of Biosensors & Bioelectronics     Open Access   (Followers: 1)
Journal of Advanced Manufacturing Systems     Hybrid Journal   (Followers: 7)
Journal of Aerosol Science     Hybrid Journal   (Followers: 2)
Journal of Aerospace Engineering     Full-text available via subscription   (Followers: 125)
Journal of Alloys and Compounds     Hybrid Journal   (Followers: 7)
Journal of Analytical and Applied Pyrolysis     Hybrid Journal   (Followers: 3)
Journal of Analytical Science & Technology     Open Access   (Followers: 4)
Journal of Analytical Sciences, Methods and Instrumentation     Open Access   (Followers: 1)
Journal of Applied Analysis     Full-text available via subscription  
Journal of Applied and Industrial Sciences     Open Access  
Journal of Applied Logic     Full-text available via subscription  
Journal of Applied Physics     Hybrid Journal   (Followers: 151)
Journal of Applied Probability     Full-text available via subscription   (Followers: 6)
Journal of Applied Research and Technology     Open Access  
Journal of Applied Science and Technology     Full-text available via subscription  
Journal of Applied Sciences     Open Access   (Followers: 5)
Journal of Architectural Engineering     Full-text available via subscription   (Followers: 5)
Journal of ASTM International     Full-text available via subscription   (Followers: 3)
Journal of Aviation Technology and Engineering     Open Access   (Followers: 6)
Journal of Biological Dynamics     Open Access   (Followers: 1)

  First | 2 3 4 5 6 7 8 9 | Last

Journal Cover Ionics
   Follow    
   Hybrid Journal Hybrid journal (It can contain Open Access articles)
     ISSN (Print) 1862-0760 - ISSN (Online) 0947-7047
     Published by Springer-Verlag Homepage  [2210 journals]   [SJR: 0.522]   [H-I: 25]
  • Reduced graphene oxide/porous Si composite as anode for high-performance
           lithium ion batteries
    • Abstract: Abstract Reduced graphene oxide/porous Si composite was fabricated through magnesiothermic reduction of mesoporous silica and subsequent dispersing porous Si in the suspension of graphene oxide followed by reduced process. The electrochemical performance of the obtained reduced graphene oxide/porous Si composite was investigated as anode for lithium ion batteries, and it delivers a reversible capacity of about 815 mAh g−1 at a rate of 100 mA g−1 in the voltage range of 0.01–1.5 V after 50 cycles. The excellent electrochemical performance of the composite can be attributed to that of the porous structure of conductive reduced graphene oxide network, and dispersed Si particles can improve electronic conductivity and accommodate the large volume changes.
      PubDate: 2014-08-16
       
  • Mesoporous carbon-sulfur composite as cathode for lithium-sulfur battery
    • Abstract: Abstract A novel carbon-sulfur composite, mesoporous carbon-sulfur, was developed as cathode of lithium/sulfur battery. The mesoporous carbon was prepared with sucrose as carbon precursor and calcium carbonate nanoparticles as pore producer. The sulfur was encapsulated in the mesoporous carbon via a simple chemical deposition strategy and a subsequent low-temperature thermal treatment process. The morphology and structure of the resulting composite were characterized with scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Brunauer-Emmett-Teller measurement, and thermogravimetric analysis. Its electrochemical performances as cathode of lithium/sulfur battery were evaluated with cyclic voltammetry and charge-discharge test. The prepared carbon showed a specific surface area of 598 m2 g−1 with a bimodal pore distribution centered at 3.6 and 40 nm. The resulting mesoporous carbon-sulfur delivered an initial capacity of 1,380 mAh g−1 at 0.02 C and maintained  a capacity of 750 mAh g−1 after 100 cycles at 0.1 C.
      PubDate: 2014-08-15
       
  • Directly carbonized lotus seedpod shells as high-stable electrode material
           for supercapacitors
    • Abstract: Abstract In this work, we demonstrate a simple and effective activation-free carbonization method to prepare porous carbon from lotus seedpod shell―a kind of natural biomass. It reveals that the carbonization temperature plays a crucial role in the determination of surface areas and capacitive performances of as-obtained porous carbon samples. The pore size and specific surface area of the samples were measured to be in the ranges of 2.0–2.2 nm and 261.7–563.4 m2 g−1, respectively. The carbon sample obtained at a carbonization temperature of 600 °C (carbon-600) exhibits the maximum Barrett–Emmett–Teller (BET) surface area of 563.4 m2 g−1 and the highest specific capacitance of 165 F g−1 at a current density of 0.5 A g−1. More importantly, the carbon-600 sample reveals unexceptionable capacitance retention of 95.3 % after 10,000 charge–discharge cycles, clearly indicating its excellent cycling stability. This work gives a simple and efficient approach for producing cost-effective porous carbons with high performance for supercapacitors.
      PubDate: 2014-08-13
       
  • Solvothermal synthesis of graphene nanosheets as the electrode materials
           for supercapacitors
    • Abstract: Abstract Graphene nanosheets (GNs) were prepared by one-pot solvothermal reduction in ethanol at different temperatures as supercapacitor electrode materials. The results of X-ray diffraction showed that the layer-to-layer distance of GNs decreased with the increase of temperature. Compared to graphite oxide (GO), these decreased values indicated that the enhanced temperature promoted the deoxidization of GO to GNs. Raman spectra showed that GNs exhibited numerous smaller disordered graphitic domains at elevated temperature. Based on the analysis results of the X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy, the higher solvothermal temperature was beneficial to remove more oxygen-containing groups of GO and obtain better quality GNs. The electrochemical performances of GNs had been studied by cyclic voltammetry and galvanostatic charge-discharge cycling techniques. The results revealed that the capacitive values increased with increasing temperature and the GNs at 493 K could provide a high specific capacitance of 186 F g−1 at a current density of 0.1 A g−1 in the 6 M KOH solution.
      PubDate: 2014-08-13
       
  • Formation of graphene nanoplatelet-like structures on carbon–ceramic
           electrode surface: application for simultaneous determination of sunset
           yellow and tartrazine in some food samples
    • Abstract: Carbon–ceramic electrode modified with 1-allyl-3-methyl imidazolium tetraflouroborate ionic liquid was constructed. Scanning electron microscopy, X-ray diffraction analysis), energy dispersive X-ray analysis proved that the deposition of ionic liquid on the surface of carbon–ceramic electrode caused formation of graphene nanoplatelet-like structures on its surface. This electrode was used for simultaneous electrochemical determination of sunset yellow (SY) and tartrazine (Tz). Operational parameters such as pH of solution and ionic liquid volume which affected the analytical performance of modified electrode were optimized. The present electrode exhibited linear response to SY and Tz in concentration range of 1 × 10−7–1.5 × 10−5 M and 1 × 10−7–2 × 10−5 M with a detection limit of 7.3 × 10−8 M and 8.1 × 10−8 M, respectively. The high repeatability, reproducibility, long-term life time, and low response time (<3 s) are advantages of modified electrode. The modified electrode was successfully applied for simultaneous determination of SY and Tz in different food samples, and the results were in good agreement with those obtained from HPLC method. Graphical abstract ᅟ
      PubDate: 2014-08-13
       
  • Electrospun preparation and lithium storage properties of NiFe       class="a-plus-plus">2O       class="a-plus-plus">4 nanofibers
    • Abstract: Abstract In this paper, we successfully synthesized NiFe2O4 nanofibers via simple electrospinning process followed by calcination process. Only peaks of NiFe2O4 could be observed from X-ray diffractometry patterns, indicating the formation of pure compound. Scanning electron microscope and transmission electron microscopy images showed the as-spun NiFe2O4 nanofibers calcined at 800 °C ranged from 130 to 220 nm in diameter. The electrochemical properties of the nanofibers anode material for lithium-ion batteries were tested. It was found that the obtained NiFe2O4 nanofibers calcined at 800 °C possessed higher reversible capacity and cycling stability than that of the samples calcined at 600 °C. The as-prepared NiFe2O4 nanofibers calcined at 800 °C exhibited a high initial discharge capacity of 1,304 mAh g−1 in the potential range of 3.0–0.01 V, and the stabilized capacity was as high as 514 mAh g−1 after 60 cycles. Moreover, the as-prepared NiFe2O4 nanofibers calcined at 800 °C also exhibited high capacity at higher charge/discharge rate.
      PubDate: 2014-08-13
       
  • Kinetics of superoxide ion in dimethyl sulfoxide containing ionic liquids
    • Abstract: Abstract The chemical generation of superoxide ion (O2 •−) by dissolving potassium superoxide was investigated. The chemically generated O2 •− was then used to study the long-term stability of O2 •− in dimethyl sulfoxide (DMSO) containing ionic liquids (ILs) and determine the rate constants based on pseudo 1st- and 2nd-order reactions between the IL and O2 •− generated in DMSO. O2 •− was unstable in DMSO containing [S222][TFSI], [DMIm][MS], [BDMIm][TfO], [EMIm][TFSI], [EMIm][MS], [P14,666][TPTP], [P14,666][TFSI], and all pyridinium-based ILs. In contrast, O2 •− was very stable in DMSO containing [MOPMPip][TFSI], [BMPyrr][DCA], [BMPyrr][TFSI], [BMPyrr][TfO], [HMPyrr][TFSI], [MOEMPip][TPTP], [BMPyrr][TFA], [N112,1O2][TFSI], and [MOEMMor][TFSI]. This shows that these ILs can be used for different applications involving O2 •−. The reaction rate constant, total consumption, and consumption rate of O2 •− were determined. The rate constants of O2 •− in some ILs were found to follow pseudo 1st-order reaction, while in others, pseudo 2nd-order reaction kinetics were observed.
      PubDate: 2014-08-13
       
  • Surfactant-mediated synthesis of ZnCo       class="a-plus-plus">2O       class="a-plus-plus">4 powders as a
           high-performance anode material for Li-ion batteries
    • Abstract: Abstract The synthesis as well as the electrochemical properties study of highly crystalline ZnCo2O4 powders is presented. ZnCo2O4 powders with a particle diameter of 15–35 nm have been successfully prepared with the surfactant-mediated method. The thorough structural characterization including X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) were employed to examine the morphology and the microstructure of the final product. The as-synthesized powders were used as anode materials for lithium-ion battery, whose charge–discharge properties, cyclic voltammetry, and cycle performance were examined and revealed very good properties. Galvanostatic cycling of ZnCo2O4 powders in the voltage range 0.005–3.0 V versus Li at 60 mA g−1 maintained charge and discharge capacities of 1,308 and 1,336 mAh g−1 after 40 cycles when cycled at 25 °C, respectively.
      PubDate: 2014-08-09
       
  • Preparation and properties of bisphenol A sensor based on multiwalled
           carbon nanotubes/Li       class="a-plus-plus">4Ti       class="a-plus-plus">5O       class="a-plus-plus">12-modified electrode
    • Abstract: Abstract A new electrochemical sensor based on the multiwalled carbon nanotube (MWCNT)/Li4Ti5O12-modified glassy carbon electrode for determination of bisphenol A (BPA) was developed by modifying the surface of a glassy carbon electrode with the prepared composite Li4Ti5O12/MWCNTs. The morphology and structure of the composite were characterized by infrared spectroscopy and scanning electron microscope. The obtained electrochemical sensor Li4Ti5O12/MWCNTs/GCE takes advantages of large specific surface area of the Li4Ti5O12 nanostructure, excellent adsorption properties, and electrochemical properties of MWCNTs. Under optimal conditions, the response of the proposed sensor to BPA was linear in the BPA concentration range from 1.0 × 10−7 to 1.0 × 10−5 mol L−1 and the detection limit was of 7.8 × 10−8 mol L−1 according to the 3σ rule. The results revealed that the newly developed sensor exhibited high sensitivity and selectivity, excellent electrochemical performance, and fast response to BPA, allowing it to be used for the detection of BPA in actual samples.
      PubDate: 2014-08-09
       
  • Polymer electrolyte for photoelectrochemical cell and dye-sensitized solar
           cell: a brief review
    • Abstract: Abstract This paper reviews the use of solid polymeric electrolyte (SPE) and gel polymeric electrolyte (GPE) in photoelectrochemical cell (PEC) and dye-sensitized solar cell (DSSC). The structure of PEC and its working principle are presented. The various types of polymer electrolytes utilized in PEC and DSSC have been highlighted in this review. It also highlights the comparison of performance of PEC and DSSC utilizing those polymer electrolytes. This review is completed with the list of other SPEs that potentially be tested in DSSC.
      PubDate: 2014-08-06
       
  • Total conductivity in Sc-doped LaTiO       class="a-plus-plus">3 + δ
           perovskites
    • Abstract: Abstract A series of Sc-doped lanthanum titanate perovskites, LaTi(1 − x)Sc x O3 + δ with x = 0, 0.2, 0.25 and 0.3, was prepared by sol-gel method. All compositions were found to exhibit orthorhombic crystal structure. An increase in unit cell volume was observed for composition with x = 0.2. The oxidation states of La3+, Sc3+ and Ti3+ ions have been established using X-ray photoelectron spectroscopy (XPS). It is observed that an enhancement in total conductivity of LaTiO3 + δ perovskite is achieved only at lower doping concentration. A reverse effect is observed for higher dopant concentration.
      PubDate: 2014-08-06
       
  • Influence of CTAB on morphology, structure, and supercapacitance of        class="a-plus-plus">β-Ni(OH)       class="a-plus-plus">2
    • Abstract: Abstract Cetyltrimethylammonium bromide (CTAB) was used as surfactants to modify the crystallization of β-Ni(OH)2 via a simple ammonia-evaporation/CTAB-induced method onto nickel foam by using a mixed aqueous solution of nickel nitrate, CTAB, and ammonia. Their structure and surface morphology are characterized by X-ray diffraction and scanning electron microscopy. The SEM images show changes in the microstructure of β-Ni(OH)2, and the XRD patterns exhibit a much higher relative diffraction intensity of (1 0 0) peaks with the addition of CTAB. The effects of CTAB content on the electrochemical behaviors of β-Ni(OH)2 are investigated by cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy. The results demonstrate that the modified β-Ni(OH)2 electrode has better electrochemical performance, such as better reaction reversibility, higher proton diffuse coefficient, higher specific capacity, and better cyclic stability. Importantly, when the CTAB content in the initial solution was 0.03 g, the results show a drastic improvement in the capacitive characteristics of β-Ni(OH)2 with a specific capacitance increases from 386 to 1,019 F g−1 at a high charging/discharging current density of 6 A g−1.
      PubDate: 2014-08-06
       
  • Ionic transport in glycerol-water mixtures
    • Abstract: Abstract Glycerol-water mixtures have been extensively studied in the past several years. One of the most used techniques to study such mixtures is dielectric spectroscopy. Here, we use it to explore the range of low frequencies. This for two main reasons: (i) although electrode polarization, occurring at frequencies below 1 kHz, is normally considered as a geometrical non-desirable effect, a detailed study of how it behaves with temperature and concentration has not been pursued, and (ii) this is the interval where the transport of ions takes place in biological cells. We found that even when the viscosity of the glycerol-water mixture is large, charge transport occurs. Our aim is to relate such results with the transport of ions in organisms that come out from hibernation.
      PubDate: 2014-08-06
       
  • Ethanol electrooxidation on PdIr/C electrocatalysts in alkaline media:
           electrochemical and fuel cell studies
    • Abstract: Abstract PdIr/C electrocatalysts in different atomic ratios (Pd:Ir 90:10, 70:30, and 50:50), Pd/C and Ir/C supported on Vulcan XC 72 carbon were tested for ethanol electrooxidation in alkaline media. The electrocatalysts were prepared by borohydride reduction method. The electrocatalysts were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS), cyclic voltammetry (CV), and chronoamperometry (CA). The XRD measurements suggested the PdIr alloy formation. EDS analyses showed the real atomic ratios similar to the nominal ones. TEM showed the average particle diameter between 4.6 and 5.8 nm for all compositions prepared. The catalytic activity for ethanol electrooxidation in alkaline medium investigated by CV and CA at room temperature showed that PdIr/C (90:10) exhibited higher performance for ethanol oxidation in comparison with others PdIr/C compositions, Pd/C and Ir/C, while the experiments on a single direct ethanol alkaline fuel cell at 70 °C showed higher performance for PtIr (70:30). The best results obtained using PdIr/C electrocatalysts may be associated to the electronic effect between Pd and Ir that might cause a decrease of poisoning on catalyst and the occurrence of bifunctional mechanism.
      PubDate: 2014-08-03
       
  • Synthesis and electrochemical properties of Li-rich cathode material
           Li[Ni        class="a-plus-plus">x Li       class="a-plus-plus">(1/3−2       class="a-plus-plus">x/3)Mn       class="a-plus-plus">(2/3−       class="a-plus-plus">x/3)]O       class="a-plus-plus">2 (       class="a-plus-plus">x = 1/4, 1/3) for
           Li-ion battery
    • Abstract: Abstract Cathode materials Li[Ni x Li(1/3−2x/3)Mn(2/3−x/3)]O2 with different content of Ni (x = 1/4, 1/3) were synthesized using co-precipitation reaction. Power X-ray diffraction measurement confirmed that the obtained Li[Ni x Li(1/3−2x/3)Mn(2/3−x/3)]O2 (x = 1/4, 1/3) possessed a layered structure and \( R\overline{3} m \) space group. Scanning electron microscopy results showed that all Li[Ni x Li(1/3−2x/3)Mn(2/3−x/3)]O2 were characterized by a large amount of micro-nanoparticles with tuck form. Based on our previous studies of conventional layered materials, powerful electrochemical evidences of charge/discharge mechanisms and electrode/electrolyte interfaces properties were given by differential capacitance curves and electrochemical impedance spectroscopy (EIS). It was found that the first charge differential capacitance curves of the Li-rich materials displayed three major reactions: the oxidation of Ni2+/4+, the extraction of oxygen and the exchange of proton, and the capacity contribution are 65.2, 25.6, and 9.2 % respectively. Nevertheless, the oxidation of Ni2+/4+ was the only reaction in the following charge processes. The EIS results showed that Li-rich material could form a stable SEI film in the charge/discharge process even though the breakdown or dissolution of the resistive SEI film appearing in the high voltage; the electronic properties changed with oxidation reactions and phase transition; and the continuous increase of the charge transfer resistance, which might be the major reason of the poor high-rate performance of Li-rich materials.
      PubDate: 2014-08-03
       
  • The influence of calcium fluoride on the electrochemical dissolution of
           chalcopyrite in sulfuric acid solution
    • Abstract: Abstract The influence of calcium fluoride on the electrochemical dissolution of chalcopyrite at pH 2 was investigated. Experimental results show, when CaF2 concentration from 0 increased to 10 mg/L, chalcopyrite corrosion current density from 0.316 μA cm−2 changed to 0.302 μA cm−2, the CaF2 inhibition efficiency is 4.43 % and up to 15.19 % when CaF2 is saturated; electrochemical impedance spectroscopy (EIS) reveals that it is the increase of the charge transfer resistance at the double layer lead to CaF2 restrain chalcopyrite corrosion; and the cause come from copper fluorinated complex formed and are absorbed on the electrode surface.
      PubDate: 2014-08-02
       
  • Electrodeposition of cobalt with tunable morphology from reverse micellar
           solution
    • Abstract: Abstract Electrodeposition of cobalt on a copper electrode was successfully performed from aqueous and reverse micellar solutions of a cationic surfactant, cetyltrimethylammonium bromide (CTAB), using constant potential electrolysis method. The potential to be applied for electrodeposition was judged from the cyclic voltammetric behavior of cobalt(II) in aqueous and reverse micellar solutions of CTAB at different compositions. The morphology, dimension, and crystallinity of cobalt deposited onto a copper substrate were evaluated from scanning electron microscopy (SEM) images and X-ray diffraction technique. The cobalt deposited on copper from aqueous solution does not show any definite shape and size, while the deposition from reverse micellar solutions occurred with definite shapes such as star-, flower-, and nanorod-like structures depending on the composition. The slow kinetics governed by the reverse micelles associated with the deposition brings about oriented growth of cobalt onto the copper substrate and offers the potential to electrochemically tune cobalt deposit with desirable morphology.
      PubDate: 2014-08-01
       
  • Advanced electrochemical performances of Li       class="a-plus-plus">4Ti       class="a-plus-plus">5O       class="a-plus-plus">12/Ag prepared by a facile
           synthesis route
    • Abstract: Abstract Spinel Li4Ti5O12 coated by highly dispersed nanosized Ag particles was synthesized via a facile and effective ultrasonic-assisted method in this paper. X-ray diffraction (XRD) results indicated that Ag was not doped into the lattice of spinel Li4Ti5O12. The as-synthesized Li4Ti5O12/Ag exhibited enhanced electronic conductivity and excellent electrochemical performances. Its electronic conductivity was increased about four times compared to that of the pristine Li4Ti5O12. Even at 10 C rate, the as-synthesized Li4Ti5O12/Ag could keep 86.5 % of the reversible capacity at 1 C rate and its reversible capacity was higher than 140 mAhg−1 whereas those were 75.3 % and 118 mAhg−1 for the pristine Li4Ti5O12.
      PubDate: 2014-08-01
       
  • Microstructural and electrochemical properties of rf-sputtered
           LiFePO4 thin films
    • Abstract: Abstract LiFePO4 has been synthesized by hydrothermal synthesis. A 2-in. sputtering target has been prepared using synthesized powder and employed for the deposition of LiFePO4 films by radio frequency magnetron sputtering. Microstructural properties have been studied by using X-ray diffraction, Raman spectroscopy, and atomic force microscope. The films deposited at 350 °C with subsequent annealing at 600 °C for 4 h exhibited well-crystallized peaks along with (101) predominant orientation which corresponds to orthorhombic olivine-type structure with Pnma space group. The electrochemical properties have been studied for films in aqueous as well as in non-aqueous media. Both the electrochemical cells at same current density of 20 μA/cm2 delivered the same initial discharge capacity around 38 μAh/cm2 μm. The Li//LiFePO4 cell exhibited good cycling stability for the first 20 cycles.
      PubDate: 2014-08-01
       
  • Studies of the electrochemical properties and thermal stability of
           LiNi1/3Co       class="a-plus-plus">1/3Mn       class="a-plus-plus">1/3O       class="a-plus-plus">2/LiFePO       class="a-plus-plus">4 composite cathodes for
           lithium ion batteries
    • Abstract: Abstract A series of LiNi1/3Co1/3Mn1/3O2/LiFePO4 composite cathodes with the LiFePO4 mass content ranging from 10 to 30 wt% were prepared by ball milling in order to combine the merits of layered LiNi1/3Co1/3Mn1/3O2 and olivine LiFePO4. The structure and morphology of the samples were characterized by X-ray diffraction and scanning electron microscope. The composite cathodes exhibited improved electrochemical performance compared with pristine LiNi1/3Co1/3Mn1/3O2. Among all the composite cathodes, the one with 20 wt% of LiFePO4 showed the best electrochemical performance in terms of discharge capacity, cycle stability, and rate capability. Electrochemical impedance spectroscopy showed that mixing of LiFePO4 in LiNi1/3Co1/3Mn1/3O2 decreased the internal resistance of the electrode, retarded the formation of SEI film, and facilitated the charge transfer reaction. Differential scanning calorimetry showed that the composite cathode had better thermal stability than pristine LiNi1/3Co1/3Mn1/3O2.
      PubDate: 2014-08-01
       
 
 
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