贮氢负极的电化学交流阻抗特性研究

AC impedence studies on metal hydride electrod

通过试验测得金属氢化物电极的电化学交流阻抗谱（ＥＩＳ），经过分析得到该电极的等效电路图。为了分析电极在不同状态下的阻抗及不同种类电极的阻抗，ＥＩＳ被用于其分析：（１）不同带电态的电极；（２）不同集流体电极；（３）不同化成态的电极。试验结果表明：（１）随放电深度的增加，电荷传递阻抗Ｒ７有先减小后增大的趋势，温伯格阻抗对应电导逐渐减小；对此进行了理论分析；（２）泡沫镍在电极中起到的集流作用不一定明显优于冲孔镍带，但可能由于镍的电催化作用，能减小电极反应的电子转移步骤阻抗；（３）以充放电方式的电化学化成主要是减小电荷转移阻抗，而对温伯格阻抗无明显影响。

Electrochemical impedance spectra (EIS) of a metal hydride electrode were interpreted by means of an equivalent circuit. To detect the resistance of different kind of electrodes and the resistance of electrode under different conditions, EIS were used to analyze electrodes with: 1. different discharge depth; 2. different current collectors; 3. different activation states. The results of the experiment showed: 1. reaction resistance R7 decreased at first and then increased with the increasing depth of discharge; 2. the contact resistance of a nickel foam electrode did not have much difference with that of a nickel belt electrode. 3. By means of charge and discharge, the formation reduced R7 remarkably, while Warburg resistance changed only a little.