Lead dioxide microfibers (MF-PbO2) were electroformed on fibers of a carbon cloth substrate in order to obtain a porous gas-evolving anode (PGEA). A solid polymer electrolyte cell was fabricated using perforated current collectors, composed of PGEA pressed against the solid polymer electrolyte using a stainless steel fine mesh as the cathode. Ex situ characterization carried out through XRD and SEM techniques provided information about the structural and morphological properties of the MF-PbO2, respectively. An electrochemical characterization study was carried out through analysis of the quasi-stationary polarization curves obtained for the oxygen evolution reaction (OER). Analysis of SEM images showed that the MF-PbO2 surface is rough and uniformly distributed along fibers of the carbon cloth substrate. The formation of MF-PbO2 occurred preferentially onto carbon fibers located near the surface of the substrate (outer fibers). The XRD study revealed a high degree of crystallinity of the beta phase (beta-PbO2), with crystals characterized by a size of 24 nm. Analysis of the Tafel plot permitted us to propose the primary water discharge as the rate-determining step for the OER. The apparent enthalpy and entropy of activation and the apparent kinetic rate constant were evaluated for the OER on MF-PbO2. The endurance test revealed that MF-PbO2 are resistant to wear during the intense oxygen evolution. (C) 2012 Elsevier Ltd. All rights reserved.