| The development of electric vehicles(EV) is imperative in order to protect environment and save energy. In the interim and near future the most promising candidate of power sources for EV is a certain type of valve—regulated lead/acid (VR-LA) batteries due to their high performance — cost ratio. Therefore, studies of PbO2 electrode as the performance determining electrode of lead/acid batteries are of great importance to improve their performance and applications to EV. Recent researches on PbO2 electrodes were reviewed and the main problems arising were analysed in this dissertation. It started with positive grid alloys and the property change of positive active materials (PAM), made a systematic and thorough study on PbO2 electrodes in the respect of basic theories and applications to deepen our understanding of microstructure of their PAM and improve their performance.The influences of bismuth on the corrosion behavior of Pb — Ca alloys were systematically studied. Bismuth is usually present in metallic lead as an impurity, and debismuthising of lead is difficult. Consequently, the effect of residual bismuth on the performance of grids and PbO2 electrodes has been the matter of great interest. Experimental results from the weight loss by constant current polarization, SEM observation, corrosion resistance determination and charge — discharge cycling showed that the corrosion — resistivity of Pb — Ca — Sn — Al alloys were increased with the increase of bismuth content in the range of 0. 0025 — 0. 0648 wt. %, and bismuth presented good effect on the cycling performance of PbO2 electrodes.On the basis of screening some inorganic and organic additives, the morphology and some related characteristics of PAM from the failed positive plates were examined by SEM observation, XRD, DTA — TG and XPS. Two failure mechanisms of PbO2 electrodes were proposed, namely, the failure of the electrodes with additive A (with ordinary capacity and longer cycle life) was due to the conversion...
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