An electrochemical investigation of mechanical alloying of MgNi-based hydrogen storage alloys

The electrochemical properties of amorphous MgNi-based hydrogen storage all oys synthesized by mechanical alloying (MA) were evaluated. The results sho w that these amorphous Mg50Ni50 alloys exhibit a higher discharge capacity and relatively good rate capacity at a suitable grinding time while their c ycle life is very poor. In order to improve the cycle life, the surface of the amorphous Mg50Ni50 alloy was coated with Ti, Al and Zr in Spex 8000 mil l/mixer and the coating effects were further investigated. Based on experim ental results, two kinds of MgNi-based amorphous alloys are designed by sub stituting part of Mg in MgNi-based alloys by suitable elements. These alloy s are then composed of four components. Thus, the cycle life of electrodes consisting of these quaternary amorphous alloys is greatly improved. (C) 20 00 Elsevier Science S.A. All rights reserved.