稀土镍系贮氢合金的放电电压平台研究

Study on discharge voltage plateau of AB_5 type hydrogen storage alloys

研究了ＡＢ５ 型贮氢合金放电电压平台与ＭＨ－Ｎｉ电池１．２ Ｖ放电电压平台之间的关系及其影响因素。结果表明，ＭＨ－Ｎｉ电池放电过程中的电压衰减主要由正极极化引起，但贮氢合金负极放电电压平台的提高有利于电池放电电压整体水平的提高，也能明显延长其１．２ Ｖ放电电压平台延续时间。贮氢合金的放电电压平台与其成分、微观组织和表面状态密切相关。就Ａ侧稀土成分而言，Ｃｅ和Ｎｄ 的影响较为明显。提高合金成分和微观组织的均匀性，并改善合金的表面状态而使其表面形成对表面电极反应有电催化作用的合金层，有利于合金放电电压平台的提高。

The relations between the discharge voltage plateau of AB 5 type hydrogen storage alloys and that of Ni MH battery and its influential factors were investigated. The results show that the discharge voltage plateau of AB 5 type hydrogen storage alloy is mainly determined by its composition, microstructure and surface character. Among A side mischmetals, Ce and Nd have greater effect than La and Pr. Improving the homogeneity of the alloy microstructure and its surface character will be beneficial to the improvement of its discharge voltage plateau.