中文摘要：

采用恒电位法、EIS分析及双电极系统对La0.8Mg0.2（Ni2.7Co0.6Al0.1Mn0.1）x（x=0.9～1.10）系列合金进行电化学性能分析。结果表明,x=1.05的合金具有较好的自放电性能（CR=97.3%）,而x=1.10的合金有较高的电化学容量（369 mAh.g-1）。合金电极的电化学阻抗谱（EIS）表明,随着化学计量比x的增大,合金电极的电荷迁移电阻先减小后增大,动力学性能先增强后减弱。线性极化测试表明,随着化学计量比x的增大,合金电极表面的电化学反应速率先增大后减小。通过合金电极阳极电流对时间响应的半对数曲线计算的氢扩散系数D随着化学计量比x的增大先增大后降低,说明合金内部的氢扩散能力先增强后降低。

英文摘要：

In this paper,the electrochemical performances of La0.8Mg0.2（Ni2.7Co0.6Al0.1Mn0.1）x（x = 0.90-1.10） hydrogen storage alloys were studied by constant potential method,EIS analysis and two-electrode system.The results show that,the alloy electrode for x = 1.05 exhibits good charge retention（CR =97.3%）,and the alloy electrode for x = 1.10 shows maximum discharge capacities（369 mAh·g-1）.Meanwhile,the results of the electrochemical impedance spectroscopy,linear polarization,anode polarization,and hydrogen diffusion coefficient measurements all indicate that the exchange current density Io,the limiting current density IL and the hydrogen diffusion coefficient D of the alloy electrodes also increase first and then reduce with the increasing of stoichiometric ratio x in alloys,which signifies that appropriate stoichiometric ratio x is favorable to improve the electrochemical kinetic property of the La0.8Mg0.2（Ni2.7Co0.6Al0.1Mn0.1）x（x = 0.90,0.95,1.00,1.05,1.10） hydrogen storage alloys.