Effects of N2 mixed gas atomization on electrochemical properties of Mm(Ni, Co, Mn, Al)5.0 alloy powder

N2 gas, Ni-Ar mixed gas and Ar gas atomization followed by acid surface treatment was applied to improve electrochemical properties of AB5 type hydrogen storage alloy powder. The shape of Ar atomized powder was spherical and it changed to be irregular with increasing N2 content of mixed gas. Irrespective of gas kinds, electrodes of atomized powder showed the same discharge capacity as cast-pulverized powder under auxiliary electrical conductivity by nickel powder addition. Without nickel powder, however, N2 atomized powder showed the best electrochemical properties as well as gas activation behavior. By the combination process of N2 gas atomization and acid surface treatment, it was considered that irregular shape of N2 atomized powder promoted electrical conductivity of electrodes and catalytic nickel concentrated surface layer was formed to increase the hydrogen storage rapidity.