Electrochemical measurements of a metal hydride electrode for the Ni/MH battery

摘要

The characteristics of the Ni/MH battery, including idscharge voltage, high-rate discharge capability and charge/discharge cycle lifetiem are mainly determined by the construction of the negative and positive electrodes and the composition ofthe hydrogen-absorbing ally. The meatl hydride (MH) alloy powder for the negativ electrode of the Ni/MH battery was first pulverized and oxidized by electrochemically charging/discharging for a number of cycles. A multicomponent AB_5-based alloy Mm_(0.95)Ti_(0.05)Ni_(3.85)Co_(0.45)Mn_(0.35)Al_(0.35) was developed as the hydrogen-absorbing alloy. The discharge characteristics of the negative electrode, including discharbge capacity, cycle lifetime and exchange current density, were studied by means of the electrochemical experiments and analysis in the experimental cell. The polarization measuremtns show that the exchange current density of the MH electrode increases with increasing number of charge/discharge cycles and then it almost remains constant after 30 cycles.