Electrochemical properties of Zr-V-Ni system hydrogen storage alloys

Abstract

The electrochemical properties of Zr-V-Ni system hydrogen storage alloys were investigated. In ZrV0.5Mn0.3Ni0.1T0.1(T = Ni, Co, Fe, Al) system alloys, higher content of V and Mn(i. e. (V+Mn)/AB2 = 0.8) brings forth more stable hydrides which have lower electrochemical capacities at room temperature. Meanwhile Al is a hydride-stabilizing element as well. The above alloys all have a capacity of about 350 mAh· g-1 by raising temperature to 328 K. The substitution of Ti for Zr obviously alleviated their hydride thermodynamic stability for Zr-Ti-V-Ni system alloys. During charging/discharging process, the preferential anodic oxidation of component elements such as Ti and V will degrade the reversible hydrogen storage ability. The result was explained by the study of XRD, SEM observation and EDS analysis.