La_(1-x)Ce_x(NiCoMnAl)_5贮氢合金电极的新型表面改性——含KBH_4碱液热充电法

New Surface Modification for La_(1-x) Ce_x(NiCoMnAl)_5 Hydrogen Storage Alloys: KBH_4 Alkaline Aqueous Solution-Hot Charging Treatment

采用还原剂热充电法对La1-xCex(NiCoMnAl) 5合金电极进行预处理。测试了电极的活化性能、最大放电容量、高倍率放电能力和氢的扩散系数 ,利用扫描电镜进行表面形貌观察和表面元素分析。结果发现处理后的合金电极在第二次充放电循环时就能完全活化 ;并且在 90 0mA/g的充放电电流密度下 ,其高倍率放电能力达到 85 %左右 ;合金电极表面出现大量的微裂纹 ,氢在处理后的合金电极中的扩散系数为 ( 2～ 3 )× 10 -9cm2 /s。因此 ,此种表面处理法有利于提高合金电极的活化性能和大电流充放电性能。

The La 1- x Ce x (NiCoMnAl) 5 alloy electrodes are pre-treated by reducing agent-hot charging treatment. The activation behavior,hydrogen diffusion coefficient and maximum discharging capacity,high rate discharging capability of alloy electrodes are tested.The surface morphology and element distribution are analyzed by scanning electron microscope.The results show that the alloy electrode is fully activated after the first charging-discharging cycle and has a high rate discharging capability of 85% at 900mA/g;The surface has a lot of micro-cracks and hydrogen diffusion coefficient is about (2～3)×10 -9 cm 2/s;Therefore,this method is good to improve activation behavior and high rate charging capacity of alloy electrode.