The effect of heat treatments and degradation behavior of high-rate dischargeability in Ti-V-based alloys as anode materials for nickel-metal-hydride batteries

The phase structure and electrochemical properties of TiV _2.1Ni_0.4Zr_0.06Cu_0.03 Cr _0.1 alloys as anode materials for nickel-metal-hydride batteries treated at different temperatures were investigated. The alloys mainly consist of a bcc (V,Ti)H_0.81 main phase and a network structure of hcp C14 laves phase, along the grain boundaries of the main phase. The lattice distortion is induced to a large extent for the sample treated at 1123 K. The electrochemical measurements indicate that the maximum discharge capacity of this sample is decreased, but improved cycling stability and high-rate dischargeability (HRD) are achieved. The deterioration behavior of the HRD for Ti-V-based alloys is discussed in the paper.