Based on thermodynamic calculations a potential/pH diagram for the Pb/H2SO4/H2O system is plotted. It defines the pH ranges of formation of the different phases and electrode systems, but the system Pb/H2SO4/H2O is kinetically controlled as well. During the anodic polarization of a lead plate immersed in sulfuric acid solution the following electrode systems form: - Lead sulfate electrode (Pb/PbSO4) in the potential region from -0.97V to -0.40V vs. Hg/HgSO4 reference electrode - Lead oxide/lead sulfate electrode (Pb/PbO/PbSO4) at potentials from -0.40V to +0.95V - Lead dioxide electrode (Pb/PbO2) at potentials above +0.95V