A-site deficient triple perovskite oxides as high-efficiency bifunctional catalysts for Zn-air batteries

The development of durable and efficient bifunctional electrocatalysts for the oxygen reduction (ORR) and oxygen evolution (OER) reactions is crucial for advancing rechargeable Zn-air batteries. In this work, an A-site-deficient triple perovskite oxide, La 1 Sr 1.5 Co 1.5 Fe 1.5 O 9-δ (LSCFO), was synthesized and applied as a bifunctional catalyst. The introduction of A-site deficiency generated oxygen vacancies and modified the electronic structure, thereby enhancing charge transfer and increasing the density of active sites. Rotating disk electrode (RDE) studies revealed excellent ORR (E 1/2 = 0.84 V) and OER (η 10 = 1.53 V) activity, with a narrow potential gap of 0.68 V. Density functional theory (DFT) calculations further confirmed that Sr incorporation tunes the electronic states of B-site cations, optimizes oxygen intermediate adsorption, and accounts for the improved OER kinetics. When integrated into a Zn-air battery, LSCFO-1:1.5 delivered 1.45 V open-circuit voltage, 108 mW cm −2 power density, and 810 mAh g Zn −1 capacity, while retaining excellent stability over 600 h of cycling.