A series of novel La_1－xSr_xNi_1－yFe_yO₃ (x＝0, 0.1, 0.2, 0.5; y＝0～1.0) perovskite oxides were prepared by sol-gel method and characterized by XRD, SEM and BET measurement. The activity of PTFE bonded bifunctional oxygen electrodes made by the perovskite-type catalyst dispersed on active carbon was investigated using steady polarization curves and electrochemical impedance spectroscopy (EIS) method. The impedance spectra of both cathodic and anodic polarization were analyzed. The electrochemical parameters of the oxygen reduction reaction were obtained by fitting the experimental impedance data to an equivalent circuit containing two Nernstian diffusion terms. The results show that the oxygen reduction activity was improved by doping Fe^3＋ ions on site B of LaNiO₃ oxides. But doping Sr^2＋ ions on site A could impair the effect because the ordering level of oxygen vacancy and electrode resistance were increased. The decomposition reaction rate of H₂O₂ catalyzed by perovskite catalysts was examined. The data showed that the catalytic activity of Ni ion was higher than that of Fe ion and when doped with Sr ion the catalytic activity of decomposition reaction rate of H₂O₂ was increased. The results of CV multi-cycle examination showed that LaNi_0.8Fe_0.2O₃ had a good electrochemical stability.

Key words: bifunctional oxygen electrode, metal-air battery, perovskite oxide, electrochemical impedance spectra, regenerative fuel cell