Mg2Ni-based hydrogen storage alloys for metal hydride electrodes

Mg2-xMxNi (M=Ti, Ce; X=0, 0.1, 0.2) and MgNi1-yNy (N=Mn, Co; y=0, 0.1, 0.2) were prepared by a powder metallurgical sintering technique. The effects o f the element substitutions and the ball-milling of the alloy, with or with out nickel powder, on the alloy properties were investigated by X-ray diffr action, transmission electron microscopy and the Malvern particle size anal yser. Three types of alloys, un-ball-milled, ball-milled without nickel pow ders and ball-milled with the addition of nickel powders, were used as the active material of metal hydride electrodes. Electrochemical measurements s how that ball-milling the alloy with or without nickel powders is an effect ive method for increasing the discharge capacity and cycle life of the allo y electrode because of the changed phase structure and surface behaviour. ( C) 1999 Elsevier Science S.A. All rights reserved.