The discharge process of nickel hydroxide electrodes obtained by electrodeposition is studied by electrochemical impedance spectroscopy (EIS). The results are discussed according to a physicochernical model, taking into account the porous nature of the electrode, the charge transfer process and the H transport in the active material. The parameter identification procedure allows estimating of values related to the interfacial area per unit volume, the solid and solution conductivities as well as diffusion and kinetic constants related to the discharge process. (C) 2008 International Association for Hydrogen Energy. Published by Elsevier Ltd. All rights reserved.