Effect of Annealing Treatment on the Phase Structure and ElectrochemicalPropertiesof La0.63(Pr0.1Nd0.1Y0.6Sm0.1Gd0.1)0.2Mg0.17Ni3.1Co0.3Al0.1 A2B7-type Hydrogen Storage Alloys
DENG Anqiang1,2, LUO Yongchun1,2, WANG Hao1, ZHAO Lei1, LUO Yuankui1
1 School of Materials Science and Engineering, Lanzhou University of Technology, Lanzhou 730050; 2 State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals,Lanzhou University of Technology, Lanzhou 730050
Abstract: La0.63(Pr0.1Nd0.1Y0.6Sm0.1Gd0.1)0.2Mg0.17Ni3.1Co0.3Al0.1 hydrogen storage alloys were prepared by high frequency induction melting, and the as-cast alloy was annealed at 900 ℃ for 24 h. A structural analysis of the alloys showed that the as-cast alloy was composed of CaCu5-type, Ce5Co19-type and Ce2Ni7-type phases, while the annealed alloy was a single phase Ce2Ni7-type structure. Both the as-cast and annealed alloy electrodes had good activation properties. Discharge curve platform became flatter and wider after annealing treatment. The corrosion potential of the two alloy electrode was basically the same, but the as-cast alloy electrode bear higher corrosion current. The cycle stability of the annealed alloy electrode (S100=83.5%) was obviously better than that of the as-cast alloy electrode (S100=69%). In 100 electrochemical charge/discharge cycles, when the charge capacity was low, the capacity of the alloy electrodes did not degraded. 90% Cmax was the charging capacity critical point of alloy electrode capacity attenuation. The kinetic properties of both the as-cast and annealed alloy electrodes were almost the same. High rate dischargeability characteristics of as-cast alloy electrode was controlled by the hydrogen diffusion rate in alloy bulk, while the annealed alloy electrode was controlled by the charge transfer on alloys surface.
邓安强, 罗永春, 王浩, 赵磊, 罗元魁. 退火处理对A2B7型La0.63(Pr0.1Nd0.1Y0.6Sm0.1Gd0.1)0.2Mg0.17Ni3.1Co0.3Al0.1[J]. 材料导报, 2018, 32(15): 2565-2570.
DENG Anqiang, LUO Yongchun, WANG Hao, ZHAO Lei, LUO Yuankui. Effect of Annealing Treatment on the Phase Structure and ElectrochemicalPropertiesof La0.63(Pr0.1Nd0.1Y0.6Sm0.1Gd0.1)0.2Mg0.17Ni3.1Co0.3Al0.1 A2B7-type Hydrogen Storage Alloys. Materials Reports, 2018, 32(15): 2565-2570.
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