A review on the development of perovskite based bifunctional electrocatalysts for oxygen electrodes in metal-air batteries

Depletion of fossil fuels, climate change, and pollution are the major concerns nowadays. This has led scientists to research clean, renewable, safe, and sustainable technologies such as energy storage, conversion systems, and energy resources, including metal-air batteries (MABs), electrolyzers, and fuel cells. Oxygen reduction reaction (ORR) and oxygen evolution reactions (OER) are the two main reactions of these devices. These devices' practical application needs to be improved by two main reactions sluggish kinetics. Catalysts that increase the selectivity and rate of these reactions are the core of such technologies. Perovskite oxides (POs) are efficient electrocatalysts for energy applications due to their flexible structure, low cost, and high intrinsic activity. There are several ways to modify perovskites' inherent characteristics, improving their catalytic activity, including oxygen deficiency, B/A site substitution, Carbon support, Co catalyst incorporation, and layered perovskites. This review discusses different types of metal air batteries, perovskite oxides as a bifunctional catalyst, and synthesis techniques and strategies to improve the catalytic activities.