贮氢合金Mm(NiCoMnAl)_5的不同制备方法对MH/Ni电池性能的影响

Effect of Preparation Method on Performance of Ni-MH Batteries for the Hydrogen Storage Alloy Mm(NiCoMnAl)_5

研究了采用悬浮熔炼(常规铸态)和不同冷却速度的单辊快淬方法制备的Mm(NiCoMnAl)5型稀土系贮氢合金负极活性材料对金属氢化物镍(MH/Ni)电池性能的影响。结果表明,采用不同方法制备的合金对整个电池活化后的容量和内阻影响很小,但是常规铸态合金在退火后降低了电池的放电电压平台,快淬合金随着冷凝速率的提高,放电平台呈降低趋势。对循环充放电过程中电池内阻、循环到一定次数时负极贮氢合金的粒度和正极内铝含量的测试结果表明,铸态不退火合金较差的抗粉化性和较差的耐腐蚀性使电池的循环性能较差,经退火后其性能均有所提高,快淬合金使电池的循环性能优于常规铸态合金。

Performance of Ni-MH batteries for the Mm（NiCoMnAl）5 alloy prepared by casting and melt-spinning techniques as negative electrode was studied. Different preparation methods show little influence on the capacity and internal resistance of the batteries, while their discharge voltage plateau decreases after annealing the as-cast alloy and also decreases with increasing solidification rate of the alloys prepared by melt-spinning technique. The internal resistance, the alloys particle size of negative electrodes and the aluminum content in positive electrodes were examined for the batteries during cycling. The results show that the cycling stability of the battery with the as-cast alloy as negative electrode deteriorates due to the rapid pulverization and poor corrosion resistance of the alloy but could be improved after annealing. Melt-spinning suppresses the pulverization and corrosion of the alloy and results in the prolonged cycle life of the batteries.