The electrochemical behaviour of Pb electrodes in 5 M H2SO4 was examined in the potential range of PbO2 stability using steady-state polarizations and voltammetry combined with potentiostatic current transient techniques. The potentiostatic electroformation of PbO2 can be mainly interpreted as an instantaneous nucleation and two-dimensional growth mechanism under charge transfer control associated with the beta-PbO2 phase generation. From the parametric identification procedure of the whole set of potentiostatic current transients and the corresponding potential dependence of the fit parameters, reasonable values of the physicochemical constants included in the reaction model have been obtained. Reaction and system modelling also take into account the contribution of the oxygen evolution reaction (OER) kinetics on the top and edges of beta-PbO2 growth centres at high overpotentials.