Modification of a rapidly solidified AB2 type hydrogen storage alloy by ball-milling

Zr0.9Ti0.1(Ni0.57V0.1Mn0.28Co0.05)(2.1) alloy was prepared by melt-spinning and ball-milled with Co3Mo additive to improve its kinetic characteristics. It was shown that after 2 h milling the alloy exhibited a much improved activation performance as well as electrochemical capacity. Electrochemical impedance experiments also showed that ball-milling of the alloy with Co3Mo could improve the surface activity to a great extent. This can be attributed to the catalytic effect of Co3Mo, which had a much closer contact with the alloy powder after ball-milling, on hydrogen oxidation. However, long time milling could decrease the capacity gradually due to the further amorphization of the alloy. The experimental results also showed that the alloy ball-milled with electrochemically catalytic material such as Co3Mo exhibited a better activity than those milled without any additives or with a metal powder such as Cu acting only as a conductor.