贮氢合金Mm(NiCoAlMn)_5粒径分布对其电化学性能的影响

Effect of Particle Size on Electrochemical Properties of Mm(NiCoAlMn)_5 Hydrogen Storage Alloy

实验研究了粉末粒度对贮氢合金Mm(NiCoAlMn) 5电化学性能的影响。在一定粒度范围内 ,合金粉越粗 ,其放电容量越大 ,倍率放电性能越好 ,循环寿命也越长。但是当平均粒度超过一定值时 ,则其放电容量却又会随粒径的增大而减小 ,混合粒径合金粉的放电容量比大径合金粉的放电容量要高。将两种不同粒度的合金粉混合使用时 ,粒径相差越大 ,堆积密度越高 ,其放电容量也就越高 ;不同配比的粗细贮氢合金粉当其质量比为 7∶3时 ,其放电容量最高。

Mm(NiCoAlMn) 5 hydrogen storage alloy was separated into three parts with average particle size of 23.77、34 57、47 36 μm respectively by water floating method.The effect of particle size on the electrochemical properties of Mm(NiCoAlMn) 5 hydrogen storage alloy was investigated through a lot of experiments.The results show that the bigger particle size, the higher the discharge capacity and the better high rate dischargeability and the longer the cycle life within some particle size. However,when the average particle size is beyond some size,the discharge capacity decreases with particle size increasing. The discharge capacity of the original powder is higher than that of the powder with the biggest size. If two types of powder with different particle size are mixed, the smaller the particle size ratio (the average particle size of small component to that of the large one), the bigger the piled density and the higher the discharge capacity. At a mixing weight ratio (the weight of large component to that of the small one) of 7∶3, the highest discharge capacity is obtained.