中文摘要：

为了探索化学计量比B／A（A和B分别为电极合金A侧和B侧元素的总和）以及Co替代Ni对ABx（x=2.5～3.5）型电极合金微观结构及电化学性能的影响，制备了电极合金La0.75Mg0.25Ni2.5Mx（M=Ni，Co；x=0，0.2，0.4，0.6，0.8，1.0）。系统地分析测试了合金的微观结构及电化学性能。结果表明，合金的微观结构与电化学性能与化学计量比B／A（相当于M含量x）密切相关。合金均具有多相结构，包括LaNi2，（La，Mg）Ni3和LaNi5相。随化学计量比B／A的增加，合金的主相由LaNi2转为（La，Mg）Ni3＋LaNi5相，并且合金的电化学性能，包括放电容量、高倍率放电能力（HRD）、放电电压特性等均显著改善。

英文摘要：

In order to investigate the influences of the stoichiometric ratios of B/A （A： gross A-site elements, B： gross B-site elements） and the substitution of Co for Ni on the structure and the electrochemical performances of the ABx（x=2.5-3.5）-type electrode alloys, the La-Mg-Ni-Co system La0.75Mg0.25Ni2.5Mx （M=Ni, Co; x = 0, 0.2, 0.4, 0.6, 0.8, 1.0） alloys were prepared by induction melting at a helium atmosphere. The structures and electrochemical performances of the alloys were systemically measured. The obtained results show that the structures and electrochemical performances of the alloys are closely relevant to the stoichiometric ratios of B/A （corresponding to M content x）. All the alloys exhibit a multiphase structure, including LaNi2, （La, Mg）Ni3 and LaNi5 phases, and the major phase in the alloys changes from LaNi2 to （La, Mg）Ni3＋LaNi5 with the variety of B/A ratio. The electrochemical performances of the alloys, involving the discharge capacity, the high rate discharge （HRD） ability and the discharge potential characteristics, significantly are improved with increasing B/A ratio.