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 + KCl mixture. The electrodeposition was conducted at 700-750 degrees 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 degrees C alloy.