Bi-functional Oxygen Electrode Using Large Surface Area Perovskite-type Oxide Catalyst for Rechargeable Metal-Air Batteries

Abstract

Abstract Gas-diffusion electrodes loaded with large surface area perovskite-type oxides, La0.6Ca0.4Co0.8B′0.2O3 (B′ = Mn, Fe, Co, Ni, Cu), were examined for the electro-chemical reduction and evolution of oxygen in 7 M KOH at 25 °C. The oxide with B′ = Fe gave the highest bi-functional performances, i.e., 200 mA/cm2 for the oxygen reduction in air and 300 mA/cm2 for the oxygen evolution at −150 and +620 mV vs. Hg/HgO, respectively, owing to its high catalytic activity for the decomposion of the HO2− intermediate.