The influence of Ga and Bi on the microstructure and electrochemical performance of Al-7Zn-0.1Sn （mass fraction,%） sacrificial anodes was investigated by means of optical microscopy （OM）,scanning electron microsco...The influence of Ga and Bi on the microstructure and electrochemical performance of Al-7Zn-0.1Sn （mass fraction,%） sacrificial anodes was investigated by means of optical microscopy （OM）,scanning electron microscopy/energy dispersive X-ray analysis （SEM/EDAX） and electrochemical measurements.It was found that the coarse dendrites structure transformed into the equiaxed grains as well as a small amount of dendrite grains after adding Ga and Bi into Al-Zn-Sn alloys.A high current efficiency of 97% and even corrosion morphology were obtained for Al-7Zn-0.1Sn-0.015Ga-0.1Bi alloy.The results indicate that the proper amount of Ga and Bi is effective on improving the microstructure and electrochemical performance of Al-Zn-Sn alloy.展开更多
Li[NixCoyMn2]O2（0.6≤x≤0.8） cathode materials with a typical hexagonal α-NaFeO2 structure were prepared utilizing a co-precipitation method.It is found that the ratio of peak intensities of（003） to（104） observ...Li[NixCoyMn2]O2（0.6≤x≤0.8） cathode materials with a typical hexagonal α-NaFeO2 structure were prepared utilizing a co-precipitation method.It is found that the ratio of peak intensities of（003） to（104） observed from X-ray diffraction（XRD）increases with decreasing the Ni content or increasing the Co content.The scanning electron microscopy（SEM） images reveal that the small primary particles are agglomerated to form the secondary ones.As the Mn content increases,the primary and secondary particles become larger and the resulted particle size for the Li[Ni（0.6）Co（0.2）Mn（0.2）]O2 is uniformly distributed in the range of100-300 nm.Although the initial discharge capacity of the Li/Li[NixCoyMn2]O2 cells reduces with decreasing the Ni content,the cyclic performance and rate capability are improved with higher Mn or Co content.The Li[Ni（0.6）Co（0.2）Mn（0.2）]O2 can deliver excellent cyclability with a capacity retention of 97.1%after 50 cycles.展开更多
In order to ameliorate the electrochemical hydrogen storage performance of La-Mg-Ni system A2B7-type electrode alloys, a small amount of Si was added. The La0.8Mg0.2Ni3.3Co0.2Six （x=0-0.2） electrode alloys were prep...In order to ameliorate the electrochemical hydrogen storage performance of La-Mg-Ni system A2B7-type electrode alloys, a small amount of Si was added. The La0.8Mg0.2Ni3.3Co0.2Six （x=0-0.2） electrode alloys were prepared by casting and annealing. The effects of adding Si on the structure and electrochemical hydrogen storage characteristics of the alloys were investigated systematically. The results indicate that the as-cast and annealed alloys hold multiple structures, involving two major phases of （La, Mg）2Ni7 with a Ce2Ni7-type hexagonal structure and LaNi5 with a CaCu5-type hexagonal structure as well as one residual phase LaNi3. The addition of Si results in a decrease in （La, Mg）2Ni7 phase and an increase in LaNi5 phase without changing the phase structure of the alloys. What is more, it brings on an obvious effect on electrochemical hydrogen storage characteristics of the alloys. The discharge capacities of the as-cast and annealed alloys decline with the increase of Si content, but their cycle stabilities clearly grow under the same condition. Furthermore, the measurements of the high rate discharge ability, the limiting current density, hydrogen diffusion coefficient as well as electrochemical impedance spectra all indicate that the electrochemical kinetic properties of the electrode alloys first increase and then decrease with the rising of Si content.展开更多
In order to evaluate the electrochemical properties of aluminum alloy anode under high current densities in alkaline electrolyte, the galvanostatic discharge, potentiodynamic polarization and hydrogen evolution tests ...In order to evaluate the electrochemical properties of aluminum alloy anode under high current densities in alkaline electrolyte, the galvanostatic discharge, potentiodynamic polarization and hydrogen evolution tests of three experimental Al?Mg?Sn?In?(Ga) alloys were performed. The results show that the alloying element gallium improves the working potentials of experimental Al?Mg?Sn?In alloys under different discharge current densities. The average working potentials of the alloys containing gallium can reach?1.3 V under current density ranging from 650 to 900 mA/cm2, while those of alloy without Ga are only?1.0 V. Such phenomenon is attributed to the solid solution which can form amalgam with aluminum matrix. Such an amalgam can form the hydrolyzed species during the discharge process and lead to the corrosion infiltrating into aluminum matrix.展开更多
As an improvement on the conventional two-layer electrode （active material layerlcurrent collector）, a novel sandwich-like three-layer electrode （conductive layerlactive material layertcurrent collector） for catho...As an improvement on the conventional two-layer electrode （active material layerlcurrent collector）, a novel sandwich-like three-layer electrode （conductive layerlactive material layertcurrent collector） for cathode material LiFePO4/C was introduced in order to improve its electrochemical performance. LiFePO4/C in the three-layer electrode exhibited superior rate capability in comparison with that in the two-layer electrode in accordance with charge-discharge examination. Cyclic voltammetry and electrochemical impedance spectroscopy indicated that Fe3＋/Fe2＋ redox couple for LiFePO4 in the three-layer electrode displayed faster kinetics, better reversibility and much lower charge transfer resistance than that in the two-layer electrode in electrochemical process. For three-layer electrode, the holes in the surface of active material layer were filled by smaller acetylene black grains, which formed electrical connections and provided more pathways to electron transport to/from LiFePO4/C particles exposed to the bulk electrolyte.展开更多
Co-P （4.9% P） powders with a chain-like morphology were prepared by a novel chemical reduction method. The Co-P and germanium powders were mixed at various mass ratios to form Co-P composite electrodes. Charge and d...Co-P （4.9% P） powders with a chain-like morphology were prepared by a novel chemical reduction method. The Co-P and germanium powders were mixed at various mass ratios to form Co-P composite electrodes. Charge and discharge test and electrochemical impedance spectroscopy （EIS） were carried out to investigate the electrochemical performance, which can be significantly improved by the addition of germanium. For instance, when the mass ratio of Co-P powders to germanium is 5：1, the sample electrode shows a reversible discharge capacity of 350.3 mA·h/g and a high capacity retention rate of 95.9% after 50 cycles. The results of cyclic voltammmetry （CV） show the reaction mechanism of Co/Co（OH）2 within Co-P composite electrodes and EIS indicates that this electrode shows a low charge-transfer resistance, facilitating the oxidation of Co to Co（OH）2.展开更多
Magnesium alloys can be developed as anode materials for seawater activated batteries. The electrochemical properties of AZ31, AP65 and Mg-3%Ga-2%Hg alloy anodes discharged in seawater were studied. The potentiodynami...Magnesium alloys can be developed as anode materials for seawater activated batteries. The electrochemical properties of AZ31, AP65 and Mg-3%Ga-2%Hg alloy anodes discharged in seawater were studied. The potentiodynamic polarization shows that the Mg-3%Ga-2%Hg alloy provides more negative corrosion potentials than AZ31 or AP65 alloy. The galvanostatic discharge results show that the Mg-3%Ga-2%Hg alloy exhibits good electrochemical properties as anodes in seawater. And the EIS studies reveal that the magnesium alloy anode/seawater interfacial process is determined by an activation controlled reaction. The Mg3Hg and Mg21Ga5Hg3 phases in Mg-3%Ga-2%Hg alloy improve its electrochemical properties better than the Mg17（Al,Zn）12 phase in AZ31 and Mg（Pb） solid solution phase in AP65 alloys.展开更多
The La-Mg-Ni-based A2B7-type La0.8-xNdxMg0.2Ni3.15Co0.2Al0.15 （x=0, 0.1, 0.2, 0.3, 0.4） electrode alloys were prepared by casting and annealing. The influences of partial substitution of Nd for La on the structure a...The La-Mg-Ni-based A2B7-type La0.8-xNdxMg0.2Ni3.15Co0.2Al0.15 （x=0, 0.1, 0.2, 0.3, 0.4） electrode alloys were prepared by casting and annealing. The influences of partial substitution of Nd for La on the structure and electrochemical performance of the as-cast and annealed alloys were investigated. It was found that the experimental alloys consist of two major phases, （La, Mg）2Ni7 phase with the hexagonal Ce2Ni7-type structure and LaNi5 phase with the hexagonal CaCu5-type structure, as well as some residual phase LaNi3 and NdNi5. The discharge capacity and high rate discharge ability （HRD） of the as-cast and annealed alloys first increase and then decrease with Nd content growing. The as-cast and annealed alloys （x=0.3） yield the largest discharge capacities of 380.3 and 384.3 mA·h/g, respectively. The electrochemical cycle stability of the as-cast and annealed alloys markedly grows with Nd content rising. As the Nd content increase from 0 to 0.4. The capacity retaining rate （S100） at the 100th charging and discharging cycle increases from 64.98% to 85.17% for the as-cast alloy, and from 76.60% to 96.84% for the as-annealed alloy.展开更多
基金Project(094200510019) supported by Technology Creative Programmer of Henan for Excellent Talents,ChinaProject(092300410132) supported by the Natural Science Foundation of Henan Province,China
文摘The influence of Ga and Bi on the microstructure and electrochemical performance of Al-7Zn-0.1Sn （mass fraction,%） sacrificial anodes was investigated by means of optical microscopy （OM）,scanning electron microscopy/energy dispersive X-ray analysis （SEM/EDAX） and electrochemical measurements.It was found that the coarse dendrites structure transformed into the equiaxed grains as well as a small amount of dendrite grains after adding Ga and Bi into Al-Zn-Sn alloys.A high current efficiency of 97% and even corrosion morphology were obtained for Al-7Zn-0.1Sn-0.015Ga-0.1Bi alloy.The results indicate that the proper amount of Ga and Bi is effective on improving the microstructure and electrochemical performance of Al-Zn-Sn alloy.
基金Project(21473258)supported by the National Natural Science Foundation of ChinaProject(13JJ1004)supported by the Distinguished Young Scientists of Hunan Province,ChinaProject(NCET-11-0513)supported by the New Century Excellent Talents in University,China
文摘Li[NixCoyMn2]O2（0.6≤x≤0.8） cathode materials with a typical hexagonal α-NaFeO2 structure were prepared utilizing a co-precipitation method.It is found that the ratio of peak intensities of（003） to（104） observed from X-ray diffraction（XRD）increases with decreasing the Ni content or increasing the Co content.The scanning electron microscopy（SEM） images reveal that the small primary particles are agglomerated to form the secondary ones.As the Mn content increases,the primary and secondary particles become larger and the resulted particle size for the Li[Ni（0.6）Co（0.2）Mn（0.2）]O2 is uniformly distributed in the range of100-300 nm.Although the initial discharge capacity of the Li/Li[NixCoyMn2]O2 cells reduces with decreasing the Ni content,the cyclic performance and rate capability are improved with higher Mn or Co content.The Li[Ni（0.6）Co（0.2）Mn（0.2）]O2 can deliver excellent cyclability with a capacity retention of 97.1%after 50 cycles.
基金Projects(50961009,51161015)supported by the National Natural Science Foundation of ChinaProject(2011AA03A408)supported by the High-tech Research and Development Program of ChinaProjects(2011ZD10,2010ZD05)supported by the Natural Science Foundation of Inner Mongolia,China
文摘In order to ameliorate the electrochemical hydrogen storage performance of La-Mg-Ni system A2B7-type electrode alloys, a small amount of Si was added. The La0.8Mg0.2Ni3.3Co0.2Six （x=0-0.2） electrode alloys were prepared by casting and annealing. The effects of adding Si on the structure and electrochemical hydrogen storage characteristics of the alloys were investigated systematically. The results indicate that the as-cast and annealed alloys hold multiple structures, involving two major phases of （La, Mg）2Ni7 with a Ce2Ni7-type hexagonal structure and LaNi5 with a CaCu5-type hexagonal structure as well as one residual phase LaNi3. The addition of Si results in a decrease in （La, Mg）2Ni7 phase and an increase in LaNi5 phase without changing the phase structure of the alloys. What is more, it brings on an obvious effect on electrochemical hydrogen storage characteristics of the alloys. The discharge capacities of the as-cast and annealed alloys decline with the increase of Si content, but their cycle stabilities clearly grow under the same condition. Furthermore, the measurements of the high rate discharge ability, the limiting current density, hydrogen diffusion coefficient as well as electrochemical impedance spectra all indicate that the electrochemical kinetic properties of the electrode alloys first increase and then decrease with the rising of Si content.
基金Project supported by the Open Fund of the State Key Laboratory of Powder Metallurgy,China
文摘In order to evaluate the electrochemical properties of aluminum alloy anode under high current densities in alkaline electrolyte, the galvanostatic discharge, potentiodynamic polarization and hydrogen evolution tests of three experimental Al?Mg?Sn?In?(Ga) alloys were performed. The results show that the alloying element gallium improves the working potentials of experimental Al?Mg?Sn?In alloys under different discharge current densities. The average working potentials of the alloys containing gallium can reach?1.3 V under current density ranging from 650 to 900 mA/cm2, while those of alloy without Ga are only?1.0 V. Such phenomenon is attributed to the solid solution which can form amalgam with aluminum matrix. Such an amalgam can form the hydrolyzed species during the discharge process and lead to the corrosion infiltrating into aluminum matrix.
基金Project(2010ZCO51)supported by Natural Science Foundation of Yunnan ProvinceProject supported by Analysis and Testing Foundation(2009-041)Starting Research Fund(14118245)from Kunming University of Science and Technology
文摘As an improvement on the conventional two-layer electrode （active material layerlcurrent collector）, a novel sandwich-like three-layer electrode （conductive layerlactive material layertcurrent collector） for cathode material LiFePO4/C was introduced in order to improve its electrochemical performance. LiFePO4/C in the three-layer electrode exhibited superior rate capability in comparison with that in the two-layer electrode in accordance with charge-discharge examination. Cyclic voltammetry and electrochemical impedance spectroscopy indicated that Fe3＋/Fe2＋ redox couple for LiFePO4 in the three-layer electrode displayed faster kinetics, better reversibility and much lower charge transfer resistance than that in the two-layer electrode in electrochemical process. For three-layer electrode, the holes in the surface of active material layer were filled by smaller acetylene black grains, which formed electrical connections and provided more pathways to electron transport to/from LiFePO4/C particles exposed to the bulk electrolyte.
基金Project supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions of ChinaProject(CXLX11_0359)supported by Research Innovative Projects for Average College Graduate Students of 2011 in Jiangsu Province,China+2 种基金Project(RERU2011010)supported by Open Subject of State Key Laboratory of Rare Earth Resource Utilization,ChinaProject(51201089)supported by the National Natural Science Foundation of ChinaProject(CPSF2012M521064)supported by China Postdoctoral Science Foundation
文摘Co-P （4.9% P） powders with a chain-like morphology were prepared by a novel chemical reduction method. The Co-P and germanium powders were mixed at various mass ratios to form Co-P composite electrodes. Charge and discharge test and electrochemical impedance spectroscopy （EIS） were carried out to investigate the electrochemical performance, which can be significantly improved by the addition of germanium. For instance, when the mass ratio of Co-P powders to germanium is 5：1, the sample electrode shows a reversible discharge capacity of 350.3 mA·h/g and a high capacity retention rate of 95.9% after 50 cycles. The results of cyclic voltammmetry （CV） show the reaction mechanism of Co/Co（OH）2 within Co-P composite electrodes and EIS indicates that this electrode shows a low charge-transfer resistance, facilitating the oxidation of Co to Co（OH）2.
基金Project (2011BAE22B03) supported by National Key Technologies R&D Program of ChinaProject (2011DFA50906) supported by the International S&T Cooperation Program of China
文摘Magnesium alloys can be developed as anode materials for seawater activated batteries. The electrochemical properties of AZ31, AP65 and Mg-3%Ga-2%Hg alloy anodes discharged in seawater were studied. The potentiodynamic polarization shows that the Mg-3%Ga-2%Hg alloy provides more negative corrosion potentials than AZ31 or AP65 alloy. The galvanostatic discharge results show that the Mg-3%Ga-2%Hg alloy exhibits good electrochemical properties as anodes in seawater. And the EIS studies reveal that the magnesium alloy anode/seawater interfacial process is determined by an activation controlled reaction. The Mg3Hg and Mg21Ga5Hg3 phases in Mg-3%Ga-2%Hg alloy improve its electrochemical properties better than the Mg17（Al,Zn）12 phase in AZ31 and Mg（Pb） solid solution phase in AP65 alloys.
基金Projects(51161015,50961009)supported by the National Natural Science Foundations of ChinaProject(2011AA03A408)supported by the National Hi-tech Research and Development Program of ChinaProjects(2011ZD10,2010ZD05)supported by the Natural Science Foundation of Inner Mongolia,China
文摘The La-Mg-Ni-based A2B7-type La0.8-xNdxMg0.2Ni3.15Co0.2Al0.15 （x=0, 0.1, 0.2, 0.3, 0.4） electrode alloys were prepared by casting and annealing. The influences of partial substitution of Nd for La on the structure and electrochemical performance of the as-cast and annealed alloys were investigated. It was found that the experimental alloys consist of two major phases, （La, Mg）2Ni7 phase with the hexagonal Ce2Ni7-type structure and LaNi5 phase with the hexagonal CaCu5-type structure, as well as some residual phase LaNi3 and NdNi5. The discharge capacity and high rate discharge ability （HRD） of the as-cast and annealed alloys first increase and then decrease with Nd content growing. The as-cast and annealed alloys （x=0.3） yield the largest discharge capacities of 380.3 and 384.3 mA·h/g, respectively. The electrochemical cycle stability of the as-cast and annealed alloys markedly grows with Nd content rising. As the Nd content increase from 0 to 0.4. The capacity retaining rate （S100） at the 100th charging and discharging cycle increases from 64.98% to 85.17% for the as-cast alloy, and from 76.60% to 96.84% for the as-annealed alloy.
