AbstractA model for the cathode potential vs. time relationship during the galvanostatic charge process for metal hydride electrodes has been derived on the basis that the adsorbed hydrogen produced at the electrode surface by charge transfer of the Volmer reaction diffuses through the bulk electrodes, i.e., α, (α+β) and β phases during the charge process, and after the absorbed hydrogen concentration in the electrodes attains a saturation value for hydrogen solution, the electrode kinetics is followed by the chemical Tafel reaction and/or the electrochemical Heyrovsky reaction. The calculated electrode potential vs. time curves are in a reasonable agreement with the experimental results of Pd hydride electrodes.