MLNi_(4-x)MnAl_x贮氢电极的交流阻抗研究

AC impedance study of MLNi_(4-x) MnAl_x hydrogen storage electrodes

MH电极的交流抗阴搞图谱由两个半圆组成,低频区大半圆对应于氢的吸收过程,高频区小半圆对应于电化学反应过程.对于MLNi_(4-x)MnAl_x电极,随着Al含量的增加,阻抗图谱低频半圆明显增大,而高频半圆几乎不变;此外、电极的循环次数、充放电状态等对阻抗图谱均有较大影响.

The electrochemical properties of MLNi4_xMnAlx hydrogen Storage electrodes have been studied by AC impedance nuethod The AC impedance measurement shows that MH electrode reaction is a multistep reaction process including charge transfer, adsorption and diffusion of hydrogen atoms in hydrogen storage alloy. The impedance diagram displays two semi-circles. The high frequency one is corresponding to electrochemical reaction process and the low frequency one is to process of hydrogen adsorption. The low frequency semi-circle is effected by cycle number charge state and composition of MH electrode.