MH/Ni电池用稀土系储氢合金的失效及回收研究

Degradation and Recovery of AB_5-Type Hydrogen Storage Alloy Used in Ni/MH Batteries

探讨了深度过放电对MH/Ni电池负极储氢合金的影响。发现在过放电后 ,负极储氢合金的XRD结构图中 ,除了储氢合金的主相外 ,还出现了十分明显的Al(OH) 3,La(OH) 3的衍射峰。结合各种情况下储氢合金失效的原因 ,利用化学处理及再熔炼的方法对失效MH/Ni电池的负极粉进行了回收实验 ,并对比了回收合金与原合金的结构及电化学性能。XRD测试结果表明回收合金与原合金的结构相同 ,均为CaCu5型。恒电流充放电实验发现 ,回收合金与原合金粉相比 ,放电容量接近 ,放电电位高。循环寿命测试结果表明 。

The influences of deeply overdischarge on the anode of Ni/MH battery were studied. After overdischarge, La(OH) 3 and Al(OH) 3 are found on the anode through XRD analysis. The hydrogen storage alloy powder from spent Ni/MH batteries was recovered by chemical and melting method according to degrading mechanism. The structure of recovered alloy was measured by XRD. The experimental results demonstrate that the alloy structure is CaCu 5 type. The constant current charge/discharge test was carried out to the original alloy and the recovered alloy. It is found that their discharge capacities are almost the same. But the discharge potential of the recovered alloy is higher than that of the original alloy. The cyclic lifetime test results demonstrate that the capacity degradation of the recovered alloy is slower than that of the original one.