The effect of temperature on electrochemical codeposition of Mg–Ni hydrogen storage alloys from molten salt system

Abstract

A Mg–Ni hydrogen storage alloy was produced as a film by molten salts electrolysis and diffusion process. Mg and Ni was co-deposition on a nickel substrate from 20 wt% MgCl2+2 wt% NiCl2 and balans NaCl + KC1 mixture. The electrodeposition was conducted at 700–750 °C and constant current density of 0.5 A cm−2 for 60 min. The phase composition and microstructure of Mg–Ni alloy were detected by X-ray diffraction (XRD) and scanning electron microscope (SEM). The electrode performance in 6 M KOH solution were characterized by cyclic charge–discharge experiment. The best initial discharge capacity (375 mAhg−1) and acceptable capacity retaining rate (70%) were obtained at the 750 °C alloy.