A Study Of The Electrochemical Performance Of α-PbO₂and β-PbO₂

Due to high oxygen evolution overpotential, good corrosion resistance under acidic conditions, excellent electrocatalytic activity, and low cost, PbO2was widely used as positive active material in lead-acid battery and as electrocatalyst in electrochemical degradation of some persistent organic pollutants. There are two different crystal structures of PbO2, namelya-PbO2and β-PbO2. a-PbO2has high electrochemical stability and relatively low electrical conductivity, whereas β3-PbO2presents high electrochemical activity and relatively high electrical conductivity. When used as the active materials of positive electrode in lead-acid battery, both PbC>2display different electrochemical properties. a-PbO2can form network in positive active materials, which is beneficial for increasing the life of PbO2electrode, but (3-PbO2possess high discharge capacity, which plays an important role in the charge-discharge cycle process of lead-acid batteries. On the other hand, a certain number of a-PbO2will transform into β-PbO2in the charge-discharge process. Although the transformation may increase the discharge capacity, it can cause the collapse of the skeleton structures, thereby reducing the utilization of the PbO2active material. Therefore, herein high-purity a-PbO2and β-PbO2powders were prepared by using simple chemical synthetic methods, and the as-prepared PbO2powders were used as positive active materials to study electrochemical performance of two types of PbO2respectively. In order to evaluate the electrochemical performance of a-PbO2and β-PbO2more accurately, we used inert the platinum nets as current collectors, and prepared the positive electrode of a lead-acid battery PbO2electrodes by mixing PbO2powder, conductive agent and adhesive by a certain percentage at first, and then pressing the obtained mixture onto a platinum net. In this way, it is possible to draw a reasonable conclusion about the influence of microstructure and morphology of PbO2materials on their electrochemical performance by reducing the influence of other additional factors. After comparing the differences in electrochemical performance between two kinds of PbO2crystals, we studied how the synergistic effect between a-PbO2and β-PbO2enhances the overall electrochemical performance of PbO2active materials.At the same time, we used EDTA modified graphene nanosheets and PbO2nanopowders to prepared PbO2/C electrodes, and investigated their charge-discharge properties. We wish to find a new path for prepare the ultrabattery based on lead-acid battery.