Abstract: V2.1TiNi0.4Zr0.06Cux (x=0-0.12) hydrogen storage alloys were prepared by induction melting with magnetic levitation, and the effects of Cu content on the microstructure and electrochemical properties of the alloys were investigated by XRD, SEM, EDS, and electrochemical test. It was found that all the alloys was consisted of a V-based solid solution main phase and a C14-type Laves secondary phase in the form of three-dimensional network. The secondary phase precipitates along the grain boundaries of the main phase. The unit cells of both main phase and secondary phase expand with increasing Cu content. The results showed that the maximum discharge capacity was improved and the activation behavior was invariable as some Cu (x=0.03-0.06) was added into the V2.1TiNi0.4Zr0.06 alloy. However, higher Cu content (x≥0.09) in the alloy impairs the discharge capacity. Furthermore, adding Cu into the V2.1TiNi0.4Zr0.06 alloy can improve its cycling stability and high-rate dischargeability significantly.

Key words: Hydrogen storage alloy, Microstructure, Electrochemical property, V-based solid solution, Cu content