Effects of surface morphology of nanostructured PbO2 thin films on their electrochemical properties

As the positive active material of lead-acid battery, microstructure and surface morphology of lead dioxide (PbO2) have a strong influence on the overall performance of lead-acid battery. In this paper, we fabricated a series of PbO2 thin films on the pure Pb surface by means of the electrochemical oxidation of Pb substrate and used the as-fabricated Pb electrodes coated with PbO2 thin films as the model electrodes to study the dependence of electrochemical properties of PbO2 materials on their microstructure and morphology, thereby providing necessary technical basis for the improvement of electrochemical performance of PbO2 active materials. Herein nanostructured PbO2 thin films were electrochemically prepared using a galvanostatic oxidation method in dilute H2SO4 solution. The electrochemical properties of the PbO2 films with different structure and morphology were investigated by using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and constant current charge/discharge methods. The results demonstrated that the PbO2 layer formed at a current density of 10 mA cm−2 possessed the higher discharge capacity and the better cycle performance than the other PbO2 layers, due to high surface area, relatively small and uniform size, and especially good connectivity between PbO2 nanoparticles. The possible factors that affect electrochemical properties of different PbO2 thin films were interpreted in detail.

► Nanostructured PbO2 thin films were fabricated on the Pb substrate by a direct galvanostatic oxidation method.
► Effects of the microstructure of PbO2 thin films on their electrochemical properties were investigated.
► The micro/nanostructured PbO2 materials can improve their electrochemical performance.