Graphitic carbon nitride (g-C3N4) based photo-assisted Li–O2 batteries: Progress, challenge, and perspective

Li-O2 batteries hold immense promise as high-performance of energy storage devices. Still, their practical application faces a significant hurdle in the form of elevated overpotentials, primarily attributed to the oxygen reduction reaction (ORR) and, notably, the oxygen evolution reaction (OER) at cathodes. The advent of photo-assisted Li-O2 batteries offers a promising solution by leveraging photocatalysts to accelerate the kinetics of ORR and OER. Among the photocatalysts available, graphitic carbon nitride (g-C3N4) becomes a focal point of interest owing to its exceptional properties and diverse applicability. This comprehensive review aims to explore g-C3N4-based photo-assisted Li-O2 batteries thoroughly. The coverage spans the structure and operational principles, a comprehensive survey of research advancements and notable exemplars, and an in-depth examination of design and enhancement strategies. The specific attributes of 2D g-C3N4 and fabrication of in-situ g-C3N4 photoelectrodes are emphasized. This review systematically delves into the current challenges faced by g-C3N4 application in photo-assisted Li-O2 batteries, while proposing possible solutions that lay foundation for the further advancement of this innovative energy storage technology.