Performance evaluation of LaNi4.7Al0.3 and LaNi5 electrodes used as anodes in nickel/metal hydride secondary batteries by analysis of current transients

The performance of LaNi4.7Al0.3 and LaNi5 porous electrodes used as anodes in nickel/metal hydride secondary batteries has been evaluated by analysis of current decay transients. From the measured three-staged current decay transients for the hydrogen transport through both electrodes in the coexistence of two hydride phases, the discharge capacity and β-to α-phase transition time were determined. The optimum charging condition and velocity of α/β phase boundary movement are discussed with respect to the experimentally obtained discharge capacity and transition time. The potentiostatic current decay transient technique is more conveniently employed to establish the optimum charging condition, as compared with the usual galvanostatic charge-discharge technique.