Review—Oxygen Electrocatalysts based on Various Modulation Strategies for Rechargeable Li-O ₂ Batteries

Li-O 2 batteries as one of the rechargeable energy storage devices have aroused considerable interests due to the pleasant energy density. However, the development and application of Li-O 2 batteries are still restricted by several challenging issues, including high overpotential, poor cycling life, and low round-trip efficiency, due to the sluggish electrochemical kinetic integrating oxygen reduction and oxygen evolution reaction (ORR, OER) in the cathode. Therefore, rationally developing innovatively bifunctional electrocatalysts is critical to alleviate the above problems. Focusing on this, in this review, we first present a brief introduction of reaction mechanism and catalysts design requirement to comprehensively understand the correlation between electrochemical performance and electrocatalysts. After that, recent progress in advanced modulation strategies for Li-O 2 batteries with vacancies engineering, doping modification, single-atom catalysis, illumination-assisted regulation, and hybrid composites synergy are systematically summarized. In this section, the electronic structure modulation, component coordination, and defect induction strategies are also introduced to enhance the electrocatalytic activity. Finally, the remaining puzzles and perspectives are highlighted. This review is instructive to provide worthy guidance for rationally designing advanced electrocatalysts in Li-O 2 batteries.