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›› 2014, Vol. 14 ›› Issue (2): 335-339.

• 材料工程专栏 • 上一篇    下一篇

La-Mg-Ni系贮氢合金相结构及电化学性能

许剑轶 胡峰 王青春 李霞 王瑞芬 张胤   

  1. 内蒙古科技大学稀土学院 内蒙古科技大学稀土学院 内蒙古科技大学稀土学院 内蒙古科技大学稀土学院 内蒙古科技大学稀土学院 内蒙古科技大学材料与冶金学院
  • 收稿日期:2014-04-22 修回日期:1900-01-01 出版日期:2014-04-20 发布日期:2014-04-20
  • 通讯作者: 许剑轶

Structure and Electrochemical Properties of La-Mg-Ni System Hydrogen Storage Alloy

XU Jian-yi HU Feng WANG Qing-chun LI Xia WANG Rui-fen ZHANG Yin   

  1. Rare Earth School, Inner Mongolia University of Science and Technology Rare Earth School, Inner Mongolia University of Science and Technology Rare Earth School, Inner Mongolia University of Science and Technology Rare Earth School, Inner Mongolia University of Science and Technology Rare Earth School, Inner Mongolia University of Science and Technology Material and Metallurgical School, Inner Mongolia University of Science & Technology
  • Received:2014-04-22 Revised:1900-01-01 Online:2014-04-20 Published:2014-04-20
  • Contact: XU Jian-yi

摘要: 采用感应熔炼法制备La0.75Mg0.25Ni3.4-xAl0.1Cox (x=0.0, 0.5, 1.0)贮氢合金,研究了合金元素Co对Ni部分替代对合金相结构及电化学性能的影响. 结果表明,合金由La2Ni7相、LaNi5相及LaMg2Ni9相组成. 随Co含量的增加,合金电极活化次数变化不大,最大放电容量、循环稳定性呈现先增后减的趋势. 合金的最大放电容量和循环保持率分别由x=0时的316.92 mA.h/g和61.83%增加到x=0.5时的340.31 mA.h/g和75.21%,而后减少到x=1.0时的333.22 mA.h/g和66.70%. 而合金的高倍率放电性能降低,当放电电流密度为900 mA/g时,其倍率放电性能由62.49% (x=0)减小到53.68% (x=1.0). 合金电极的极限电流、贮氢合金电化学反应电阻逐渐增大,其高倍率放电性能的降低源于电极表面的电子迁移速率和氢在合金体相中扩散速率的共同作用.

关键词: 贮氢, La-Mg-Ni合金, 晶体结构, 电化学性能, 电极

Abstract: The hydrogen storage alloy La0.75Mg0.25Ni3.4-xAl0.1Cox (x=0.0, 0.5, 1.0) was prepared by induction smelting. The effect of partial replacement of Ni by Co in the alloy on its structure and electrochemical properties was studied. The results show that the alloy consists of La2Ni7 and LaMg2Ni9 phases and LaNi5 phase of CaCu5 type. The replacement of Ni by Co had a little effect on the activation property of alloy electrodes. The discharge capacity and cyclic stability of alloy electrodes increase first from 316.92 mA.h/g and 61.83% (x=0) to 340.31 mA.h/g and 75.21% (x=0.5), and then decreases to 333.22 mA.h/g and 66.70% (x=1.0) with increasing of Co content. The high rate discharge ability decreases with the addition of Co content. At the discharge current density of 900 mA/g, the high rate discharge ability of alloy electrodes decreases from 62.49% (x=0) to 53.68% (x=1.0). The substitution leads to some increase in the limiting current density and electrochemical impedance spectroscopy. The deterioration of its high rate discharge ability can be ascribed to the synergic effect of electron transfer on the alloy surface and hydrogen diffusion in the bulk of alloy.

Key words: hydrogen storage, La-Mg-Ni alloy, crystalline structure, electrochemical property, electrode

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