( 1. 西安交通大学 金属材料强度国家重点实验室， 西安 710049；
2. 陕西省锅炉压力容器检测所， 西安 710049)
摘 要: 通过感应容炼制备了La0.8-xRExMg0.2Ni3.2Co0.6(RE=Sm, Dy, 0 ≤x ≤ 0.3) 合金。 采用X射线衍射分析了该合金的晶体结构， 并研究了其电化学性能。 结果表明: 该合金是由LaNi5主相和LaNi3第二相构成; 随着Sm(Dy)取代La量的增加， 合金主相单胞体积线性收缩， 合金储氢量和放电容量减小， 当Sm(Dy)取代量分别为0.1、 0.2、 0.3时， 合金容量由380 mA·h/g分别减小到370(362)、 355(334)、 329(295) mA·h/g， 但高倍率放电能力和循环稳定性得到改善， 100次循环后的容量损失率由20%分别降低到18%(17%)、 16%(14%)、 13%(11%)。
关键字: 镍氢电池； 储氢合金； 稀土； 放电容量
（ 1. State Key Laboratory for Mechanical Behavior of Materials,
Xi'an Jiaotong University, Xi'an 710049, China;
2. Shaanxi Measurement Institute for Boiler Pressure Vessel, Xi'an 710049, China）
Abstract: La0.8-xRExMg0.2Ni3.2Co0.6(RE=Sm, Dy, 0≤x≤0.3) alloys were prepared by inductive melting. The crystal structure of the alloys was determined by X-ray powder diffractrometry and the electrochemical properties were investigated. The results show that the alloys are composed of LaNi5 as matrix and LaNi3 as secondary phase. With the increasing Sm (Dy) substitution for La, the unit cell volume of matrix of the alloys shrinks linearly and both the hydrogen storage capacity and discharge capacity decrease. When the Sm (Dy) substitution (x value) is 0.1, 0.2 and 0.3, the discharge capacity decreases from 380 mA·h/g to 370(362), 355(334) and 329(295) mA·h/g, respectively. However, the rate performance and cycle stability is improved. After 100 cycles, the capacity loss decreases from 20% to 18%(17%), 16%(14%) and 13%(11%).
Key words: nickel-metal hydride battery; hydrogen storage alloy; rare earth; discharge capacity
