The cyclic voltammetry of lead, antimony and lead + antimony binary alloys has been studied in 0.5 M H2SO4 solution at 25-degrees-C between the hydrogen and oxygen evolution potentials and over narrower potential regions. This investigation, together with systematic variation of the scan rates and the positive or negative reversal potential, has revealed more details of the oxidation and reduction processes which give further insight into the nature of reactions in the lead-acid battery. Voltammetry data were interpreted taking into account nucleation and growth models, thermodynamic data and the electronic properties of the surface compounds in the potential region of species containing Pb(II), Pb(IV) and Sb(III). The conditions under which PbO and PbO2 formation can be seen in the positive sweep have been determined.