Advances of the bifunctional electrocatalyst toward oxygen reduction/evolution reaction

The development of economical, highly efficient, and stable bifunctional electrocatalysts for both the oxygen evolution reaction (OER) and the oxygen reduction reaction (ORR) remains a critical focus in advancing rechargeable metal-air battery systems. Significant progress has been made in the design of high-performance bifunctional electrocatalysts, the development of novel oxygen electrode architectures, and the in-depth understanding of electrocatalytic mechanisms through combined experimental and computational studies. This work provides a comprehensive review of recent advancements in design strategies for oxygen catalysts, including homogeneous electrodes, asymmetric electrodes, and biomimetic electrodes, are thoroughly discussed and summarized. Then, the advanced catalyst modification strategies for ORR/OER are summarized, focusing on critical factors such as enhancement effect of metal/nonmental and synergistic enhancement effect in multiple catalyst. Subsequently, a representative performance evaluation is presented, based on the reported oxygen electrodes used in rechargeable metal-air battery applications. By focusing on these key areas, the review outlines the current challenges and future prospects for the development of bifunctional oxygen electrocatalysts, aiming to guide the design of high-performance bifunctional electrocatalysts and to elucidate the underlying mechanisms involved.