The influence of the addition of polycrystalline Pt, Pd and Ni powders into hydride-forming metal alloy electrodes on the activation process, rate-capability and cycling stability has been evaluated. The metal powder additives were found to improve the activation rate and to decreased the overpotentials of the charge and discharge processes. The electrochemical properties of these modified electrodes were analysed in terms of a simplified form of a previously developed model. Electrochemical impedance spectroscopy measurements were performed to allow the validation of the model and the identification of kinetic and physicochemical parameters.