Nanocrystalline structure and electrochemical hydrogen storage properties of the as-milled Mg–V–Ni–Fe–Zn-based materials

Abstract

Among the electrode materials for Ni-MH batteries, the Mg alloy electrodes such as MgNi, Mg2Ni, REMg12, La2Mg17 are considered the most suitable anode materials due to their high discharge capacity and low cost. However, the poor electrochemical cycling stability prevents its practical application. In this paper, Mg50-xVxNi45Fe3Zn2 (x = 0, 1, 2, 3, 4) + 50 wt% Ni alloys were prepared by partially replacing Mg with V and using mechanical ball milling techniques with amorphous and nanocrystalline structures. Electrochemical tests showed that the ball-milled alloy had good electrochemical uptake and release performance. The maximum release performance is achieved in the first cycle. After that, the discharge level and cycle stability increased significantly with increasing ball grinding time and V content.