Effect of Al and Ce substitutions of the electrochemical properties of amorphous MgNi-based alloy electrodes

Mg-based hydrogen storage alloys Mg0.9Al1.0-xCexNi (x = 0.00, 0.01, 0.02, 0.025, 0.075) were successfully prepared by means of mechanical alloying (MA). The structure and the electrochemical characteristics of these Mg-based electrodes were also studied. The result of X-ray diffraction (XRD) shows that the main phases of the alloys exhibit amorphous structures. The charge-discharge cycle tests indicate these alloys have good electrochemical active characteristics. Among these alloys, the Mg0.9Al0.08Ce0.02Ni has the best cycle stability. After 50 cycles charge-discharge, the discharge capacity of Mg0.9Al0.08Ce0.02Ni alloy is 66.67% higher than MgNi alloy. The cyclic voltammograms (CV), electrochemical impedance spectroscopy (EIS) and anticorruption test (potentiodynamic polarization) were also studied, and the results show that the electrochemical cycle stability of these alloys was improved by Al and Ce substitutions. (C) 2006 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.