Rationalizing Electrocatalysis of Li-S Chemistry by Mediator Design: Progress and Prospects

The lithium-sulfur (Li-S) battery is regarded as a next-generation energy storage system due to its conspicuous merits in high theoretical capacity (1672 mAh g(-1)), overwhelming energy density (2600 Wh kg(-1)), and the cost-effectiveness of sulfur. However, the practical application of Li-S batteries is still handicapped by a multitude of key challenges, mainly pertaining to fatal lithium polysulfide (LiPS) shuttling and sluggish sulfur redox kinetics. In this respect, rationalizing electrocatalytic processes in Li-S chemistry to synergize the entrapment and conversion of LiPSs is of paramount significance. This review summarizes recent progress and well-developed strategies of the mediator design toward promoted Li-S chemistry. The current advances, existing challenges, and future directions are accordingly highlighted, aiming at providing in-depth understanding of the sulfur reaction mechanism and guiding the rational mediator design to realize high-energy and long-life Li-S batteries.