Electrochemical properties of the amorphous Ti ₃Ni ₂ alloy in Ni/MH batteries

Amorphous Ti ₃Ni ₂ (Ti ₂Ni/TiNi) alloy has been prepared by mechanical milling of crystalline Ti ₃Ni ₂ alloy, and its electrochemical properties were investigated. The results of charge and discharge test show that the amorphous Ti ₃Ni ₂ alloy can resolve the problem of extremely short cycle life of crystalline Ti ₃Ni ₂ alloy at high temperature (333 K). The capacity retention rate of amorphous Ti ₃Ni ₂ alloy is greatly increased to 88.83% at 333 K compared with the retention rate of its crystalline counterpart 39.47% after 19 cycles. Based on analysis of Tafel polarization, linear polarization, and electrochemical impedance spectroscopy, it is found that the major reason for the improvement is the presence of amorphous Ti ₃Ni ₂ alloy, which has much better corrosion resistance compared with its crystalline counterpart.