Modulation of perovskite electronic configuration by cobalt doping for efficient catalysts in zinc-air battery electrodes

An in-depth comprehension of the structural characteristics of perovskite and the response mechanisms is crucial for designing materials with excellent properties. Here, the performance of several kinds of Sr 0.75 Pr 0.25 Fe 1-x Co x O 3-δ (x = 0, 0.25, 0.5, 0.75, 1) in an alkaline environment was thoroughly examined. Sr 0.75 Pr 0.25 Fe 0.25 Co 0.75 O 3-δ displayed the lowest overpotential (337 mV @ 10 mA·cm −2 ) and Tafel slope (69.3 mV·dec −1 ) in 0.1 M KOH and possessed excellent performance in zinc-air batteries. Cobalt doping encourages the positive shift of the O 2p band center, boosting the number of electrons around the Fermi energy level and delivering an increase in conductivity, according to DFT and experimental studies. Compared to Sr 0.75 Pr 0.25 FeO 3-δ , the rate-limiting step of Sr 0.75 Pr 0.25 Fe 0.25 Co 0.75 O 3-δ changes from OH*→O* deprotonation to OH* adsorption, which significantly decreases the energy potential barrier during OER process. The A/B site doping method is universal and facile, which is essential to comprehend and develop effective perovskite oxide for zinc-air battery electrodes.