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Articles 2731 - 2760 of 3176

Full-Text Articles in Engineering Science and Materials

Fabrication Of SncuX/Cms Composite Materials For Lithium-Ion Batteries, Yu Liu, Jing-Ying Xie, Jun Yang, Ke Wang, Bao-Feng Wang Feb 2003

Fabrication Of SncuX/Cms Composite Materials For Lithium-Ion Batteries, Yu Liu, Jing-Ying Xie, Jun Yang, Ke Wang, Bao-Feng Wang

Journal of Electrochemistry

The composite material were prepared by sub-ctrochemical cycling tests showed that coulombic efficiency of the electrodes prepared by the composite materials was near 100 % after second cycle and the capacity dropped less than 5% after the 30th cycle, versus 390 mAh⋅g-1 special capacity, improving 26% special capacity of pure CMS electrode. The electrochemical performance of the composite materials is depended strongly on the alloy content in the composite, the addhesive strength between alloy particles and CMS matrix, the distribution of particles on the surface of CMS and the particle size of alloy. The composite material can be applied …

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Pure Iron Electrolyzed From Scrap Iron Chips And Its Corrosion Characteristics, Wei-Min Cao, Ren-He Yin, Hui-Ceng Yan, Zhi-Qiang Ye Feb 2003

Pure Iron Electrolyzed From Scrap Iron Chips And Its Corrosion Characteristics, Wei-Min Cao, Ren-He Yin, Hui-Ceng Yan, Zhi-Qiang Ye

Journal of Electrochemistry

The high purity electrolytic iron was made from scrap iron chips. Electrolytic conditions of pure iron were determined in chloride baths and the highest purity was 99.983% by chemical analysis. Pure iron had very compact texture and high mechanical strength by SEM figures of cross section. In deaerated 0.5 kmol·m-3 H2SO4 and 0.5 kmol·m-3 NaCl solutions, the corrosion rate of iron decreased with increasing purity.

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Electroreduction Of Cd(Ⅱ) In Dmso And Complexation Of Cd(Ⅱ) With Coumarin Derivates, Ji-Guo Song, Hua-Can Song, Qi-Qin Yang, Yi-Wen Chen, Zun-Le Xu Feb 2003

Electroreduction Of Cd(Ⅱ) In Dmso And Complexation Of Cd(Ⅱ) With Coumarin Derivates, Ji-Guo Song, Hua-Can Song, Qi-Qin Yang, Yi-Wen Chen, Zun-Le Xu

Journal of Electrochemistry

Cadmium p-toluenesulfonate was synthesized and tested electrochemically for the first time. This salt can lose all the hydrated water easily and the dehydrated salt do not deliquesce in the air.Hence,the cadmium p-toluenesulfonate is suitable for the electrochemical studies in organic solvents.When the Cd(Ⅱ) reduced on Pt electrode in Cd(p-CH3C6H4SO3)2+TBAP+DMSO, underpotential deposition of cadmium occurred at first, and then cadmium deposited. 4-Methyl-7-hydroxylcoumarin and 3-aminocoumarin coordinate with Cd(Ⅱ) respectively, as a result the reductive potentials of Cd(Ⅱ) moved to the negative direction.

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Magnetic Resonance Studies On Lithium Intercalation Into Carbons, Xiao-Rong Zhou, Zhen-Ming Du, Lin Zhuang, Jun-Tao Lu Feb 2003

Magnetic Resonance Studies On Lithium Intercalation Into Carbons, Xiao-Rong Zhou, Zhen-Ming Du, Lin Zhuang, Jun-Tao Lu

Journal of Electrochemistry

The electron spin resonance(ESR) and 7Li-NMR magnetic resonance (7Li-NMR) studies on lithium intercalation into carbons were reviewed based on recently published papers, including those by the authors of this review. Two kinds of electronic spins were found in ESR studies. One corresponds to the charge carrier electrons and is called the Pauli spin. From the ESR intensity of Pauli spins, the curve of the density of electronic states can be deduced for the carbon material studied and, in turn, the contribution of the band model mechanism to the lithium intercalation can be calculated for the given carbon sample. The other …

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Study Of Electrochemical Lithium Intercalation Performance Of Ni0.67Mg0.33O, Zhen-Cai Huang, Mao-Hui Chen, Guo-Tao Wu, Jin-Kua You, Zu-Geng Lin Feb 2003

Study Of Electrochemical Lithium Intercalation Performance Of Ni0.67Mg0.33O, Zhen-Cai Huang, Mao-Hui Chen, Guo-Tao Wu, Jin-Kua You, Zu-Geng Lin

Journal of Electrochemistry

In the present work, Ni0.67Mg0.33O and NiO were produced by sol-gel method, and characterized by XRD, a rietveld refinement and the discharge/charge test.It was found that the magnesium-doping restrained the reduction of Ni and decreased the reversible capacity for the sample of Ni0.67Mg0.33O. But the formation of the solid solution after the magnesium-doping facilitated the high dispersion of NiO, and accordingly improved the electrochemical performance.

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Application Of Biphenyl Electroploymerization For Overcharge Protection In Li-Ion Batteries, Li-Fen Xiao, Xin-Ping Ai, Yu-Liang Cao, Han-Xi Yang Feb 2003

Application Of Biphenyl Electroploymerization For Overcharge Protection In Li-Ion Batteries, Li-Fen Xiao, Xin-Ping Ai, Yu-Liang Cao, Han-Xi Yang

Journal of Electrochemistry

The electropolymerization of biphenyl at overcharged positive electrode was investigated for overcharge protection of Li-ion batteries. Biphenyl in electrolyte as an additive can electrochemically polymerize at 4.5～4.75 V(vs. Li/Li+) to form a layer of conductive film on cathode surface. The surface film increases the internal resistance and the gases released during the electropolymerization also increases the internal pressure of the batteries, which therefore enhance the sensitivities of the electrical disconnecting devices. During prolonged overcharge, the growth of the conductive polymer film can create short circuit between the positive and negative electrodes and cause self-discharge of the batteries to …

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The Preparation And Characterization Of Zno-Pani Composite Film, Yan-Yan Xi, Huai-Guo Huang, Zhi-Xin Zheng, Ping Dong, Jian-Zhang Zhou, Ling-Ling Wu, Zhong-Hua Lin Feb 2003

The Preparation And Characterization Of Zno-Pani Composite Film, Yan-Yan Xi, Huai-Guo Huang, Zhi-Xin Zheng, Ping Dong, Jian-Zhang Zhou, Ling-Ling Wu, Zhong-Hua Lin

Journal of Electrochemistry

ZnO nanoparticle films were prepared on the Au film, PANI film and ITO by sol-gel method, and their morphological optical and photoelectrochemical properties were also studied. The results showed that the porous structure of PANI can suppress the aggregation of ZnO particles, resulting in the blue shift of on-set in the UV-Vis spectra and fluorescence spectra of ZnO-PANI composite film compared with that of ZnO-Au film. It was suggested that the ZnO-PANI composite film can be used in photoelectric coversion.

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The Electrochemical Behavior Of Amorphous Ni-P And Ni-B Alloys In 0.5 Mol/L H2So4, Xu-Cheng Wang, Wei-Jiang Wang, Hou-Tian Liu, Zu-Zhan Yu Feb 2003

The Electrochemical Behavior Of Amorphous Ni-P And Ni-B Alloys In 0.5 Mol/L H2So4, Xu-Cheng Wang, Wei-Jiang Wang, Hou-Tian Liu, Zu-Zhan Yu

Journal of Electrochemistry

Polarization curves and impedance spectra were used to investigate the electrochemical behavior of amorphous Ni-P and Ni-B alloys in 0.5 mol/L H2SO4 solutions. The possible reason about the remarkable difference in the electrochemical behavior between amorphous Ni-P and Ni-B alloys was discussed.

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Behaviors Of Fe-Cr Alloys During Cavitation Damage, Xia Bai, Dong-Bai Sun, Hong-Ying Yu, Hui-Ming Meng, Hui-Qin Li, Zi-Shuang Fan Feb 2003

Behaviors Of Fe-Cr Alloys During Cavitation Damage, Xia Bai, Dong-Bai Sun, Hong-Ying Yu, Hui-Ming Meng, Hui-Qin Li, Zi-Shuang Fan

Journal of Electrochemistry

The influence of the surface galvanic effect on the behaviors of three Fe-Cr alloys during cavitation damage in NaCl solutions have been investigated. The results showed that the galvanic effect caused by the inhomogeneity between the undamaged surface of the alloy and the damaged one will be enhanced by the area ratio of the undamaged and the damaged. The behaviors of alloys during cavitation are closely related to both their mechanical performance and anti-corrosion capabilities.

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Study On The Corrosion & Electrochemical Properties Of Alloy Aa5083 And The Effect Of Active Chlorine In Seawater, Hong-Ren Wang, Jian-Hua Wu, Jun-Tao Wang, Hong-Bin Wang, Zhi-Gang Fang Feb 2003

Study On The Corrosion & Electrochemical Properties Of Alloy Aa5083 And The Effect Of Active Chlorine In Seawater, Hong-Ren Wang, Jian-Hua Wu, Jun-Tao Wang, Hong-Bin Wang, Zhi-Gang Fang

Journal of Electrochemistry

In this paper potentiodynamic technique, cyclic polarization technique and immersion corrosion method were used to study the corrosion and electrochemical properties of AA5083 alloy in quiescent seawater, the effect of active chlorine on its properties was also studied. The results obtained indicate that the active chlorine has no remarkable impact on the corrosion and electrochemical properties of AA5083 alloy in area of design concentration which range from 0.2 to 0.5 mg/L, and it has favorable influence on the improvement of pitting corrosion resistance. While the pH value of seawater has evident influence on the corrosion resistance of AA5083 alloy.

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Study For The Cathodic Behavior Of Active Chlorine On 316l Ss Electrode Surface, Hui Yu, Ming-Xian Sun, Yan Ma, Xiao-Bin Wang Feb 2003

Study For The Cathodic Behavior Of Active Chlorine On 316l Ss Electrode Surface, Hui Yu, Ming-Xian Sun, Yan Ma, Xiao-Bin Wang

Journal of Electrochemistry

The cathodic reducing reactions of active chlorine on 316 L SS electrode surface have been investigated by electrochemical techniques. The open circuit potential shifted positively and the limited diffusion current density increased significantly with the increasing content of active chlorine in the 3.5% sodium chloride solution. The two cathodic reduction processes of HClO and ClO- exhibited on the surface of electrode with the active chlorine added to the 3.5%sodium chloride solution and the corresponding potentials of the two reducing reactions were confirmed. The linear relationship of the mass transport-limited Faradaic current, Id vs. the square root of the angular …

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Development And Study Of The (Ag)-Ni/Cr Composite Plating With Antibacterial Properties And Corrosion Resistance, Ya-Ping Zhao, Jin-Hua Wang, Ren-He Yin, Jin Zheng, Le-Shu Yu Feb 2003

Development And Study Of The (Ag)-Ni/Cr Composite Plating With Antibacterial Properties And Corrosion Resistance, Ya-Ping Zhao, Jin-Hua Wang, Ren-He Yin, Jin Zheng, Le-Shu Yu

Journal of Electrochemistry

The 3-factor and 3-level orthogonal experiment was designed and through the comparison of the different films' antibacterial properties measured by bacterial colony counting and the corrosion resistance studied with the AC impedance method. The optimal plating conditions of the (Ag)-Ni/Cr composite plating, a novel functional plating, were determined. The results have indicated that the (Ag)-Ni/Cr composite plating is characterized by both antibacterial and corrosion resisting properties and has its wide applied prospect.

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Synthesis By Complexation Processes And Characterization Of Lini0.8Co0.2O2 Cathode Materials, Jing Liu, Zhao-Yin Wen, Zhong-Hua Gu, Xiu-Jian Zhu, Zu-Xiang Lin Feb 2003

Synthesis By Complexation Processes And Characterization Of Lini0.8Co0.2O2 Cathode Materials, Jing Liu, Zhao-Yin Wen, Zhong-Hua Gu, Xiu-Jian Zhu, Zu-Xiang Lin

Journal of Electrochemistry

The layered LiNi0.8Co0.2O2 compound, which has been of great interest for lithium ion batteries, was prepared at low temperatures by calcining a complex precursor at different temperatures. The physical properties of the synthesized cathode materials were discussed in the light of structural (XRD). The charge and discharge cycling of the cells containing the synthesized oxide as the positive electrode in conjunction with lithium metals and employing a non-aqueous electrolyte showed that LiNi0.8Co0.2O2 treated at 900 ℃ exhibited excellent performances. The first discharge capacity of LLiNi0.8Co0.2O2 …

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Lithium Intercalation Performance Of P-Doped Phenolic Resin Pyrolysis Carbon, Bao-Hua Li, Kai-Xi Li, Yonggen Lv, Chun-Xiang Lv, Dong Wu, Li-Cheng Ling Nov 2002

Lithium Intercalation Performance Of P-Doped Phenolic Resin Pyrolysis Carbon, Bao-Hua Li, Kai-Xi Li, Yonggen Lv, Chun-Xiang Lv, Dong Wu, Li-Cheng Ling

Journal of Electrochemistry

Phosphorus-doped phenolic resin carbon was prepared by low temperature (700 ℃) pyrolysis of thermoplastic phenolic resin containing different amounts of phosphorus pentoxide after curing. X-ray diffraction pattern and the constang-current charge-discharge properties of phenolic resin carbon were studied. The results showed that the phenolic resin carbon microstructure became out of order with increasing of content phosphorus pentoxide, otherwise, the first discharge reversible capacities increased firstly and then decreased. The first discharge reversible capacity of phenolic resin carbon containing 9wt% phosphorus pentoxide was 528 mA·h·g-1 which was higher than that of non-phosphorus doped phenolic resin carbon(230 mA·h·g-1) did.

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Studies On The Inhibition Of Yki-05 Corrosion Inhibitor To 907a Steel In Different Immersed Environments, Hui Yu, Jian-Hua Wu, Hong-Ren Wang, Jian-Hua Qian, Guang-Zhang Chen Nov 2002

Studies On The Inhibition Of Yki-05 Corrosion Inhibitor To 907a Steel In Different Immersed Environments, Hui Yu, Jian-Hua Wu, Hong-Ren Wang, Jian-Hua Qian, Guang-Zhang Chen

Journal of Electrochemistry

The inhibition of YKI-05 Corrosion inhibitor in different conditions was studied using potentiodynamic polarization technique. The resuled shown that (i) the inhibitor film layer was formed stably on the surface of 907A steel electrode when it was persistently immersed in static seawater and the inhibition efficiency reached 90% or so. The inhibition mechanism is negative catalytic effect. (ii) the inhibitior film layer was not stable when the electrode was periodically immersed in seawater and was destroyed more significantly with the increase of electrode exposing time. The film was only a covered layer on the surface of electrode and it retarded …

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Preparation And Performance Of Lifeo2 Coated Nickel Oxide Cathode For Molten Carbonate Fuel Cells, Chun-Ming Wang, Fei Li, Ke-Ao Hu Nov 2002

Preparation And Performance Of Lifeo2 Coated Nickel Oxide Cathode For Molten Carbonate Fuel Cells, Chun-Ming Wang, Fei Li, Ke-Ao Hu

Journal of Electrochemistry

A novel cathode for molten carbonate fuel cells was prepared by coating LiFeO2 over the surface of porous NiO cathode by a simple combustion process. The analytical results of X-ray diffraction (XRD), energy dispersive analysis of X-ray (EDAX), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) indicated that the LiFeO2 coating on the surface of NiO particles consisted of nonometer-sized LiFeO2 grains and sintered tightly with the NiO particles. The LiFeO2 coating dramatically reduced the contacting area of NiO with the carbonate melts, thus the solubility of NiO in the carbonate melts was decreased. Meanwhile, …

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Review Of Mathematical Model For Proton Exchange Membrane Fuel Cell, Shan-Hai Ge, Bao-Lian Yi, Hua-Min Zhang Nov 2002

Review Of Mathematical Model For Proton Exchange Membrane Fuel Cell, Shan-Hai Ge, Bao-Lian Yi, Hua-Min Zhang

Journal of Electrochemistry

In the review with 49 references, the mathematical models for proton exchange membrane fuel cell (PEMFC) were summarized. The mechanistic model and empirical model were introduced. Transfer in the membrane, catalyst layer, diffusion layer and flow field of PEMFC were described. The importance of water and heat management was analyzed. The dimension, complexity and solving methods of the PEMFC model were discussed. The importance and validity to develop a model with time dimension are put forward.

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Mechanistic Study Of Oxidation Of Hypophosphite On Pt Electrodes By Sniftirs, Tai-Xiang Jiang, Hui-Huang Wu Nov 2002

Mechanistic Study Of Oxidation Of Hypophosphite On Pt Electrodes By Sniftirs, Tai-Xiang Jiang, Hui-Huang Wu

Journal of Electrochemistry

The oxidation of hypophosphite on a polycrystalline platinum electrode was studied by SNIFTIRS and cyclic voltammetry, the in-situ IR spectra were analyzed as a function of Pt electrode potentials in the solution of 0.5 mol/L H2SO4+0.1 mol/L NaH2PO2. It was found that the dissociative adsorption of hypophosphite ions occurs on Pt surface, and the oxidation product is H3PO4, rather than H2PO3- which was considered to produce on Ni electrodes, thereby a new insight into mechanism of hypophosphite oxidation on Pt in acidic media was …

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Preparation And Electrochemical Lithium Intercalation Performance Of Different Shaped Carbon Nanotube, Mao-Hui Chen, Zhen-Cai Huang, Guo-Tao Wu, Jin-Kua You, Zu-Geng Lin Nov 2002

Preparation And Electrochemical Lithium Intercalation Performance Of Different Shaped Carbon Nanotube, Mao-Hui Chen, Zhen-Cai Huang, Guo-Tao Wu, Jin-Kua You, Zu-Geng Lin

Journal of Electrochemistry

In the present work, different shaped carbon nanotubes were produced by the general CVD and the template method at different temperature (600 ℃,700 ℃) with the reaction gas of acetylene. The morphology, structure and the electrochemical lithium intercalation performance were comparatively studied and characterized by TEM, HRTEM, SEM, XRD, Raman techniques and Charge/Discharge Test. It was found that the different preparation methods and temperatures all had an obvious effect on these properties of carbon nanotubes. In our samples, with the increase of preparation temperature, the degree of crystallinity decreased, and the reversible specific capacity increased respectively.

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Nano-Sized Cobalt-Based Oxides As Negative Electrode For Lithium-Ion Batteries, Feng Huang, Zheng-Yong Yuan, Yun-Hong Zhou, Ju-Tang Sun Nov 2002

Nano-Sized Cobalt-Based Oxides As Negative Electrode For Lithium-Ion Batteries, Feng Huang, Zheng-Yong Yuan, Yun-Hong Zhou, Ju-Tang Sun

Journal of Electrochemistry

Nanosized cobalt-based oxide (Co3O4, CoB1.36O2.8 and CoB0.5Al0.1O1.5) samples were prepared by rheological phase method and were tested as anodes in secondary lithium batteries. The cells were cycled between 0.01V and 3.00 V. The best electrochemical performance was obtained from the Co3O4 cell, which retained 95% of its initial capacity (931 mAh/g) after 30 cycles. The doping of B, Al reduced the reversible capacity during the first discharge/charge cycle, and the quantity of reversible capacity reduced with B, Al increasing. The modifying structures at difference …

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Properties Of Domestic Natural Graphite Used For Li-Ion Batteries, Cui-Wei Du, Yu-Juan Zhao, Gang Zhang, Yin-Shun Wu, Qing-Guo Liu Nov 2002

Properties Of Domestic Natural Graphite Used For Li-Ion Batteries, Cui-Wei Du, Yu-Juan Zhao, Gang Zhang, Yin-Shun Wu, Qing-Guo Liu

Journal of Electrochemistry

The structure, physical characteristics and electrochemical properties of the natural graphite produced in Shandong province have been studied. The result of X-ray diffraction showed that the graphite consisted of hexagonal structure and rhombic structure (30% rhombic structure). It was fine crystal graphite. Used as a negative material of Lithium ion battery, the natural graphite showed excellent voltage and high energy capacity, but poor compatibility with electrolyte solution containing propylene carbonate (PC) for its own structure limitation.

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Effect Of Dissolved Oxygen On The Corrosion Behavior Of Coalesced Copper And Stainless Steel-206 In Acetic Solutions, Rong-Zong Hu, Xiong-Cao Zhao, Yu-Hua Weng, Chang-Jian Lin Nov 2002

Effect Of Dissolved Oxygen On The Corrosion Behavior Of Coalesced Copper And Stainless Steel-206 In Acetic Solutions, Rong-Zong Hu, Xiong-Cao Zhao, Yu-Hua Weng, Chang-Jian Lin

Journal of Electrochemistry

Linear sweeping technique and dissolving oxygen sensor were used to study the effect of dissolved oxygen and relating factors on the corrosion behavior of coalesced copper and stainless steel-206 in acetic solutions. It was found: 1. The existing of dissolved oxygen is one of the important factors, which strongly influenced the corrosion behavior of coalesced copper and stainless steel-206 in acetic solution. 2. The existing of dissolved oxygen is benefitial to the preventing stainless steel-206 from corrosion in acetic solutions, but damage to the preventing coalesced copper from corrosion. 3. At the high temperature since the dissolved oxygen was escaping …

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Electrocatalytic Oxidation Of Formic Acid On Molybdate-Modified Platinum Electrode, Jun-Hua Du, Xue-Hui Xu, Hong Li, Hong-Yu Cheng, Wei-Shan Li Nov 2002

Electrocatalytic Oxidation Of Formic Acid On Molybdate-Modified Platinum Electrode, Jun-Hua Du, Xue-Hui Xu, Hong Li, Hong-Yu Cheng, Wei-Shan Li

Journal of Electrochemistry

The electrochemical behavior of molybdates on a platinum electrode in H2SO4 solutions with different H2SO4 concentrations was studied by cyclic voltammetry and double chronoamperometry. Molybdates were reduced to adsorb hydrogen molybdenum bronzes on the platinum electrode in H2SO4 solutions during cathodically potential sweep. The hydrogen molybdenum bronzes were oxidized to different forms of hydrogen molybdenum bronzes with less hydrogen, depending on the H2SO4 concentration. Platinum electrode was modified by these hydrogen molybdenum bronzes. However, this modified electrode was not stable in H2SO4 solutions. The modified …

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Improvement Of The Low Temperature Electrochemical Performance Of Ab5-Type Hydrogen Storage Alloy, Hui Ye, Zhu Wu, Zhi-Lin Li, Hong Zhang Nov 2002

Improvement Of The Low Temperature Electrochemical Performance Of Ab5-Type Hydrogen Storage Alloy, Hui Ye, Zhu Wu, Zhi-Lin Li, Hong Zhang

Journal of Electrochemistry

Optimizing the rare earth composition and doping with boron have been used to improve the low temperature performance of AB5 hydrogen storage alloy. The results show that Ce-rich alloy with a proper amount of boron is suitable for Ni/MH battery with the lower-limit temperature down to 238 K under smaller current density (≤120 mA/g). The improvement of low temperature performance of hydrogen storage alloy is well consistent with its microstructure, thermodynamic and kinetic properties.

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Manufacture Of 1 Kw Molten Carbonate Fuel Cell Stack, Sheng Sui, Xin-Jian Zhu, Zheng-Yu Fan, Guang-Yi Cao Nov 2002

Manufacture Of 1 Kw Molten Carbonate Fuel Cell Stack, Sheng Sui, Xin-Jian Zhu, Zheng-Yu Fan, Guang-Yi Cao

Journal of Electrochemistry

A molten carbonate fuel cell stack with an active area of 240 mm×140 mm consisted of 30 cells. The gas feed system works via interior manifolds, and the stack placed in a couple of self-chest, coupled with a heater at the bottom and other fours surrounded,to keep uniformity of temperature.Under ambient pressure and 650 ℃, fed with hydrogen and air as anode and cathode gases respectively, the stack gave a current density of 150 mA/cm2 at an average cell voltage of 0.7 V. The peak output of the stack was 1.06 kW during its performance of 300 h.

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Steady State Simulation Of Ysz Intermediate-Temperature Fuel Cell, Zi-Jing Lin, Ye Gu, Xiao-Hua Zhang Nov 2002

Steady State Simulation Of Ysz Intermediate-Temperature Fuel Cell, Zi-Jing Lin, Ye Gu, Xiao-Hua Zhang

Journal of Electrochemistry

With a coupled 2D electrochemical and thermal modeling software, the characteristics of the steady state operation of the intermediate-temperature fuel cell with thin yttria-stabilized zirconia(YSZ) electrolyte was analyzed. The parameters of I-V equation were obtained from fitting the experiment results and the choice of grid points was determined by balancing the accuracy requirement and computational efficiency. The temperature fields at different operation circumstances such as flow designs, material choices for interconnect, were examined. The dependences of the output power and cell efficiency on the operating voltage at different temperatures were studied. Based upon the analysis of the temperature profile, it …

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Optimum Of Catalyst Layers For Direct Methanol Fuel Cells, Jun Zhang, Lei Li, Li Xu, Yu-Xin Wang Aug 2002

Optimum Of Catalyst Layers For Direct Methanol Fuel Cells, Jun Zhang, Lei Li, Li Xu, Yu-Xin Wang

Journal of Electrochemistry

The performances of membrane electrode assemblies (MEAs)with various Pt loading were compared. The amount of Nafion in a catalytic layer was optimized, and the effect of Nafion loading on the resistance of MEAs was investigated with ac impedance spectroscopy. For a MEA with both Pt 4 mg/cm2 in the anode and the cathode, suitable Nafion loading was 21.4 wt% in the anode. With 21.4 wt% Nafion loading in the cathode, the Direct Methanol Fuel Cells(DMFC) showed the highest performance at high current density. While, the DMFC performances came down, as Nafion loading increasing,for ohm and concentration polarization.

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Electrochemical Properties Of Nitrate Immobilized On Gold Electrodes With 2-Aminoethanethiol Sams, Ya-Ru Song, Hong Wu, Hui-Bo Shao Aug 2002

Electrochemical Properties Of Nitrate Immobilized On Gold Electrodes With 2-Aminoethanethiol Sams, Ya-Ru Song, Hong Wu, Hui-Bo Shao

Journal of Electrochemistry

Nitrate reductase (NR) and phospholipids were immobilized on gold electrodes with 2-aminoethanethio(AET) SAMs. After Au/AET/NR and Au/AET/NR/lipid were soaked in pH 7 phosphate buffers for days, a pair of pre-reversible peak appeared at around 0.202 V and 0.149 V respsctively, irregularly grew with soaking time in blank buffer.The cathodic peak current (ipcl) of Au/AET/NR system had linear relationship with scan rate between 0.02 and 0.5 V⋅s-1 ,while ipcl was proportional to V1/2 in Au/AET/NR/lipid system. The direct electron transfer of enzyme electrodes was strongly affected by pH. Compared with Au/AET, NR exhibited a higher electrochemical …

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Electrochemical Techniques For Measuring Anti-Corrosion Behavior Of The Thin Corrosion Inhibitor Layer To The 907a Steel, Yong-Tao Zhao, Jian-Hua Wu, Fan-Cai Chen, Zhong-Ping Gao, Jia Wang, Chang-Jiu Zhao Aug 2002

Electrochemical Techniques For Measuring Anti-Corrosion Behavior Of The Thin Corrosion Inhibitor Layer To The 907a Steel, Yong-Tao Zhao, Jian-Hua Wu, Fan-Cai Chen, Zhong-Ping Gao, Jia Wang, Chang-Jiu Zhao

Journal of Electrochemistry

The corrosion inhibiting behavior of 907A steel, which was covered with thin inhibitor layers in moist seawater atmosphere,was studied. The electrochemical measurements, including EIS method and the coulostatic method, were used to atmospheric corrosioed monitor (ACM) under thin inhibitor layers to determine its corrosion rate. The results shown that the application of electrochemical methods such as the coulostatic technique and EIS could readily detect the on going process of film formation. Hence, the rapid evaluation of the thin inhibitor layers for 907A steel might be possible.

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Synthesis And Characterization Of Lini0.8-XAlXCo0.2O2 As Cathodes For Lithium-Ion Batteries, Jun Zhang, Zhong-Kao Jin, Qing-He Yang, Qing-Mei Song, Xiao-Hua Ma, Xiang-Fu Zong Aug 2002

Synthesis And Characterization Of Lini0.8-XAlXCo0.2O2 As Cathodes For Lithium-Ion Batteries, Jun Zhang, Zhong-Kao Jin, Qing-He Yang, Qing-Mei Song, Xiao-Hua Ma, Xiang-Fu Zong

Journal of Electrochemistry

Single-phase solid solution of LiNi0.8-xAlxCo0.2O2 (0≤ x <0.1)had been synthesized and characterized by X-ray diffraction(XRD) and scanning electron microscopy (SEM). Their electrochemical performance was examined by charge-discharge cycling. The LiNi0.71Al0.09Co0.2O2 compound showed a discharge capacity of 152 mAh/g after 20 cycles that corresponds to 97.4% capacity retention. The beneficial effect of co-doping with Al and Co elements was corro-borated by slow scanning cyclic voltammograms(SSCV), electrochemical impedance spectrum (EIS) and differential scanning calorimetry (DSC) data on charged cathodes. These results show that the 2D-character of the crystal lattice was stabilized by co-doping with Al and Co, the phase transitions that occur during deintercalation or intercalation of Li-ions were significantly suppressed, …

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