Electrochemical characteristics of Mg2Ni-type alloys prepared by mechanical alloying

Abstract The electrochemical characteristics of Mg 2 Ni-type hydrogen storage alloys prepared by mechanical alloying (MA) using a planetary ball mill were investigated. The structures of three alloys were characterized by XRD and SEM. Results of XRD indicated that the structure of the synthesized alloys changed with milling time from polycrystalline to nanocrystalline or amorphous. In charge–discharge cycle tests, the partial substitution of Al and V for Mg increased the discharge capacity of Mg 2 Ni alloy at 25°C. The discharge capacity of the 80-h milled Mg 1.5 Al 0.3 V 0.2 Ni at 25-mAg −1 discharge current density reached 435 mAhg −1 . The poor cycle life of Mg-based alloys is a critical problem in spite of their high capacity. It was found that the addition of Al could lead to an improvement of the cycling stability.