Influence of perfluorinated surfactants on the positive active-material of lead/acid batteries

The influence of perfluorinated anionic (FC-99), cationic (FC-135), and non-ionic (FSN) surfactants on the discharge capacities and cycle live of Planté positive electrodes in sulfuric acid are studied by cyclic voltammetry, charge/discharge cycling, X-ray diffraction, and scanning electron microscopy. The discharge capacities of PbO2 electrodes, i.e., the utilization of the positive active-material, are increased for the electrolytes with FC-99 or FC-135, but the cycle live both surfactants are reduced. On the other hand, the presence of FSN has negligible influence on the discharge capacity and the cycle life of the PbO2 electrode. The differences in the effects of the various types of perfluorinated surfactants are discussed with respect to the adsorption of perfluorinated surfactant molecules on the PbO2 electrode surface during the charge and/or the discharge process.