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双辊淬冷法制备稀土镍基贮氢合金及其晶粒尺寸和电化学性能

吕东生1; 李伟善1; 唐仁衡2; 肖方明2   

  1. 1. 华南师范大学化学系, 广州 510631; 2. 广州有色金属研究院, 广州 510651
  • 收稿日期:2004-06-14 修回日期:2004-08-10 出版日期:2005-07-20 网络出版日期:2005-07-20

Crystallite Size and Electrochemical Performance of Metal Hydrides Based on LaNi5 Prepared by Twin-Roll Process

LU Dong-Sheng1; LI Wei-Shan1; TANG Ren-Heng2; XIAO Fang-Ming2   

  1. 1. Department of Chemistry; South China Normal University; Guangzhou 510631; China; 2. Guangzhou Institute for Nonferrous Metal Research; Guangzhou 510651; China
  • Received:2004-06-14 Revised:2004-08-10 Published:2005-07-20 Online:2005-07-20

摘要: 使用双辊淬冷技术制备了LaNi5AB5型贮氢合金,用扫描电镜和X射线衍射确定合金的晶粒尺寸,用恒电流充放电方法确定合金的电化学容量及其循环稳定性.结果表明, 制备的合金具有均匀的纳米晶结构;在64mA/g(约0.2C)的电流密度下,合金放电容量高达336mAh/g,而在640mA/g(约2C)的电流密度下,合金放电容量仍达312mAh/g,经400次循环后容量保持约80%.另外,还研究了La含量对合金容量和循环稳定性的影响,合金容量在La 含量<60%范围内,随La含量增加而增加,La含量从60%增至80%,合金容量保持不变, 但是合金循环稳定性随La含量增加而减少.

关键词: 双辊淬冷法, 贮氢合金, 容量, 循环稳定性, 晶粒尺寸

Abstract: AB_5-type hydrogen storage alloy La0.65Ce0.28Pr0.02Nd0.05Ni3.8Co0.7Mn0.3Al0.2 was prepared by twin-roll process, and the microstructure, capacity and cyclic
stability of the alloy were characterized by SEM, XRD and constant current charge and discharge. The alloy has a uniform nano-scale crystallite size
of about 40nm. Its discharge capacity is 336mAh/g at 0.2C rate (64mA/g), and 312mAh/g at 2C rate (640mA/g) and retains 80% of the initial capacity after
400 cycles. The influence of La content on electrochemical capacity and cyclic stability of the alloy was also studied. It is found that discharge capacity
of the alloy increases with the increase of La content when La less than 60wt% and keeps unchanging from 60% to 80%. However, cyclic stability of
the alloy decreases with the increase of La content.

Key words: twin-roll process, hydrogen storage alloy, capacity, cyclic stability, crystallite size

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