An Electrochemical Investigation of Mg-Ni Hydrogen Storage Alloys by Mechanical Alloying

Abstract

The characteristics and mechanisms of enhanced electrochemical properties for Mg-Ni alloy produced by mechanical alloying MA were investigated by electrochemical measurements. Electrochemical hydrogen storage properties were characterized by cyclic charge-discharge experiment, electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization methods. The phase composition and microstructure of Mg-Ni alloy were detected by X-ray diffraction (XRD) and scanning electron microscope (SEM). XRD showed that the alloys exhibit dominatingly amorphous structures. And also, 20 h milling was enough to obtain amorphous/nano-crystalline alloy structure. The best initial discharge capacity (489 mA h g(-1)) and acceptable capacity retaining rate (48%) were obtained for the 20 h milled Mg50Ni50 alloy.