The analysis of the two discharge plateaus for Ti–Ni-based metal hydride electrode alloys

In some conditions, the multi-phase composition of the hydrogen storage electrode alloy can be reflected on its discharge curve. In this paper, the discharge curves of the Ti–Ni-based hydrogen storage alloys have be analyzed using electrochemical techniques and XRD. We concluded that the appearance of the two discharge plateaus on the discharge curves of the Ti0.5Al0.25Ni0.25 alloy and Ti3Ni1.7M0.3 (M=Ni, Al, Co, Cr) alloys is related to their multi-phase composition and multi-phase hydride formation. The appearance of the first fastigiated plateau is the result of together releasing hydrogen of TiNi and Ti2Ni phases. The secondary flat plateau represents releasing hydrogen process of only the Ti2Ni phase.