Hydrogen adsorption of metal nickel and hydrogen storage alloy electrodes

Abstract

An improvement in the electrocatalytic activity of the hydrogen storage alloy electrodes is essential to ensure a high rate capability of an Ni–MH battery. Previous experimental results showed that there was a hydrogen adsorption phenomenon on the alloy surface and the activation energy barrier of the electrochemical reaction process should be reduced by hydrogen adsorption. Therefore, the hydrogen adsorption is of benefit in improving the electrocatalytic activity of the alloy electrode. In this work, the hydrogen adsorption performance on the surfaces of Zr(V 0.2Mn 0.2Ni 0.6) 2.4, MmNi 3.6Mn 0.4Co 0.75Al 0.25 alloy electrodes and carbonyl nickel electrode was measured by means of cyclic voltammetry. In addition, the hydrogen adsorption performance of the metal nickel ribbon was performed by electrochemical impedance spectra. The results showed that the Ni sites on the surface of the metal hydride electrodes play an important role in the hydrogen adsorption.