Effect of perfluoroalkylsulfonate on the discharge behaviour of PbO2 electrodes in sulfuric acid solution

Amine perfluoroalkylsulfonate (FC-99) is seen as a prospective additive for lead/acid battery positive plates. Accordingly, its effect on the electrochemical behaviour of PbO2 electrodes in 5 M H2SO4 is studied by cyclic voltammetry, charge/discharge cycling and scanning electron microscopy. For sulfuric acid solution with FC-99, the discharge capacity of the PbO2 electrode is increased, but the cycle life is reduced. These effects are attributed to adsorption of FC-99 on the electrode surface. The latter changes the morphology of the PbO2 crystals to enlarge the electrode surface area, but weakens the contact between the positive active material and the substrate metal.