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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。
The electrochemical properties of La0.8Mg0.2 (Ni2.7Co0.6Al0.1Mn0.1) x (x = 0.9 ~ 1.10) alloys were investigated by potentiostatic method, EIS analysis and two-electrode system. The results show that the alloy with x = 1.05 has better self-discharge performance (CR = 97.3%) and the alloy with x = 1.10 has higher electrochemical capacity (369 mAh.g-1). Electrochemical impedance spectroscopy (EIS) showed that the charge-transfer resistance of the alloy electrode first decreased and then increased with the increase of the stoichiometric ratio x, and the kinetic properties first increased and then decreased. Linear polarization test shows that with the increase of stoichiometry x, the electrochemical reaction rate of the electrode surface first increases and then decreases. The hydrogen diffusion coefficient D calculated from the semi-logarithmic curve of the anode current versus the time response of the alloy electrode first increases and then decreases with the increase of the stoichiometric ratio x, indicating that the hydrogen diffusion capacity inside the alloy firstly increases and then decreases.