AC impedance behaviour and state-of-charge dependence of Zr0 × 5Ti0 × 5V0 × 6Cr0 × 2Ni1 × 2 metal-hydride electrodes

Metal-hydride electrodes made of an AB2 alloy of the composition Zr0,5Ti0,5V0,6Cr0,2Ni1,2are studied for AC impedance behaviour at several of their state-of-charge values. Impedance data at any state-of-charge comprise two RC-time constants and accordingly are analysed by using a nonlinear-least-square-fitting procedure. Resistance of the electrode and frequency maximum ( f *) of the lowfrequency semicircle are found useful for predicting state-of-charge of the metalhydride electrodes.