Nanophase PbO~2 was prepared successfully by solid-phase redox reaction and characterized by XRD, TEM and CV techniques. The synthesis conditions of nanophase materials were discussed. PbO~2 modified MnO~2 electrodes were fabricated and their electrochemical properties were studied by means of constant current discharge and CV experiments. The results indicated that the optimum ratio of PbO~2 additives were 1.25%～5.00%. The charge-discharge mechanism of MnO~2 changed because the Pb(X)(X=0, Ⅱ) and Mn(Y)(Y=Ⅳ，Ⅲ，Ⅱ) atoms formed stable complexes. These complexes could be cooxidized and coreduced and thus restrained the formation of electrochemically inactive Mn~3O~4. The rechargeability of the MnO~2 electrode could be improved. Discharge mechanism of MnO~2 doped with nanophase sample was similar to that doped with conventional sample(S). But the nanophase sample was more effective in modifying MnO~2 electrode than the conventional sample. The discharge capacity of the nanophase PbO~2 modified MnO~2 electrodes were in average 30% higher than that of the conventional PbO~2 modified ones.

Key words: LEAD OXIDE, NANOPHASE MATERIALS, MANGANESE OXIDE, MODIFICATION, X-RAY DIFFRACTION ANALYSIS, CYCLOVOLTAMGRAPH