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.