Low-temperature synthesis of La0.8Sr0.2Co0.8X0.2O3-δ (X = Fe, Mn, and Ni) perovskite oxides for bifunctional oxygen electrodes

Perovskite oxides are increasingly recognized as cost-effective catalytic materials for facilitating both the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) at the air-electrode electrode of Zn-air batteries (ZABs) and fuel cells. In this study, we have employed a non-hydrolytic sol-gel (NHSG) technique to synthesize La 0.8 Sr 0.2 Co 0.8  X  0.2 O 3-δ (X = Fe, Mn, and Ni) perovskite nanoparticles at a low temperature of 600 °C. Among these perovskite oxides, La 0.8 Sr 0.2 Co 0.8 Fe 0.2 O 3-δ (LSCFO) exhibited the highest specific surface area of 12.68 m 2  g −1 and possessed the greatest number of oxygen vacancies. Specifically, it achieved a higher half-wave potential of 0.657 V for ORR. Meanwhile, it exhibited a lower OER overpotential of 418 mV at a current density of 10 mA cm −2 , along with the smallest ΔE value of 0.991 V. When utilized as an air electrode catalyst for ZABs, LSCFO exhibits a high peak power density of 152.2 mW cm −2 and remarkable long-term cycling stability (100 h at 2 mA cm −2 ), which are close to the performance metrics of commercial Pt/C + RuO 2 catalysts. This study demonstrates the potential to enhance the bifunctional catalytic activity of LaCoO 3 -based perovskite air electrodes for ZABs through a straightforward doping approach within a NHSG process.