MmNi_(3.8-x)Co_xMn_0.4Al_0.3合金的结构与电化学性能

Structure and Electrochemical Property of the MmNi 3 8-x Co xMn 0 4 Al 0 3 Alloys

本文对ＭｍＮｉ３．８－ｘＣｏｘＭｎ０．４Ａｌ０．３（ｘ＝０．２、０．４、０．５、０．６、０．７和０．９）进行了物相分析和电化学测试。发现Ｃｏ部分取代Ｎｉ可在不改变合金相结构和起始活化性能的前提下改善合金的循环稳定性，但同时降低了合金的起始放电容量特别是高倍率放电容量。合金的初始放电电压随Ｃｏ含量的增加而增加，但放电电压平台特性随Ｃｏ含量的增加而劣化。Ｃｏ含量对合金的容量、循环稳定性的影响并不是线性的，而是存在拐点，拐点前后合金上述电化学性能随Ｃｏ含量变化的幅度有着较大的差别。

The phase structure and electrochemical property of the alloys with compositions of MmNi 3 8-x Co xMn 0 4 A 0 3 (x=0.2、0 4、0 5、0 6、0 7and0 9) have been investigated in detail.The partial substitution of Co for Ni can improve the cycle stability of the alloy and decrease the initial discharge capacity,especially the high rate capacity,without altering the phase structure and initial activation rate of the alloy.With the increasing Co content,the voltage at the starting discharge stage becomes higher,but the discharge plateau becomes slope.The above properties do not change linearly with Co content.There is certain Co content more or less than which the degree of the property changes due to Co substitution is very different.