MlNi_4Mn贮氢电极的电化学研究

ELECTROCHEMICAL STUDIES OF MlNi_4Mn HYDROGEN STORAGE ELECTRODE

利用循环伏安、电位阶跃和交流阻抗等电化学方法对 Ml Ni4Mn( Ml:富镧混合稀土金属 )贮氢电极进行了研究 .实验结果表明 ,Ml Ni4Mn电极循环伏安曲线氧化峰电流 Ip与扫描速度 v1 /2成线性关系 ,说明贮氢电极反应为扩散控制过程 ;氢原子在贮氢合金中的扩散系数与电极的荷电状态有关 ,随着电极中氢原子含量增加而增大 ;Ml Ni4Mn电极的交流阻抗图谱由两个半圆组成 ,高频区 ( 6.3～ 10 0 k Hz)小半圆对应于电化学反应过程 ,低频区 ( 0 .1～ 11.3 Hz)

The characteristics of MlNi 4Mn hydrogen storage electrode have been studied by using cyclic voltammetry,potential step,a.c.impedance methods.The experimental results shows that the cyclic voltammetry of MlNi 4Mn electrode exhitbites a good linear relationship between I p and v 1/2 ,suggesting MlNi 4Mn electrode reaction being controlled by diffusion process.The diffusion coefficient of H atom in MlNi 4Mn alloy is related to charge states of electrode,is increased with increasing H atom contents.The impedance diagram displays two semi-circles.The high frequency (6.3～100kHz) one is corresponding to electrochemical reaction process and the low frequency (0.1～11.3Hz)one is to process of hydrogen adsorption.