采用真空快淬法研究制备了富铈稀土系低温贮氢合金,考察了3种不同组成合金的放电性能.结果表明,Mm(NiCoAlMn)_(4.95)舍金大电流放电性能较好;添加微量元素后,可以2提高其0.7C放电比容量、放电平台以及改善循环性能.经循环伏安性能测试发现,氢在合金电极中的扩散系数(D_H=3.90×10~(-8)cm~2/s)较大;XRD分析显示合金具有单一CaCu_5型相结构,晶粒尺寸小于50nm.用此合金组装的D8500型镍氢电池在-40℃、0.2C电流条件下,放电容量达到常温放电容量的70.72%.以1C电流充放电400次,电池容量保持率为93%,完全满足低温镍氢电池的要求.%The Mm rare earth hydrogen storage alloy is synthesized by vacuum rapid quenching method. And three different alloys are studied. The results show that the alloy of Mm(NiCoAlMn)_(4.95) has better large-current discharging performance. And its electrochemical properties, such discharge capacity, discharge voltage platform, cyclic life as well, are improved obviously. The bigger hydrogen coefficient(D_H= 3.90×10~(-8) cm~2/s)of alloy electrode is obtained by cyclic voltammetry. While the single CaCu_5-type phase structure of the alloy is determined by XRD, and its small grain size is less than 50nm. Then, the discharge capacity of D8500 Ni/MH battery, the alloy as material, can reach 70.72% of normal atmospheric temperature capacity at -40℃ by 0.2C. Moreover, the cell after 400 cycles at 1C, the capacity still has 93%, which satisfies the need of battery at low temperature.
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