Abstract: Lithium-sulfur (Li-S) batteries are considered appealing power sources due to their high theoretical energy density (2600 Wh kg^-1), low cost, and environmental friendliness. However, their widespread applicability is restricted by two scientific problems: sluggish sulfur reaction kinetics and severe polysulfide shuttle effects. Multifarious strategies have been developed to overcome these two obstacles and achieve high sulfur utilization and capacity retention. Among these strategies, the introduction of catalytic materials into the Li-S battery system can greatly accelerate sulfur conversion and effectively inhibit the polysulfide shuttle effects. Herein, we have comprehensively reviewed the recent progress of catalytic engineering for polysulfide conversion in high-performance lithium-sulfur batteries. First, various catalytic materials serve as sulfur hosts, functionalized separators, and electrolyte additives; the mechanisms by which these materials promote the conversion of polysulfides in Li-S batteries have been systematically summarized. The relationship of structure, preparation, property, advantages, and limitations of these catalytic materials are comprehensively presented. Subsequently, the advanced characterization techniques of these catalytic processes are discussed, shedding light on the fundamental understanding of catalytic effects for improved electrochemical performance. Furthermore, future design tactics for high-performance Li-S batteries are discussed.

Key words: Lithium-sulfur battery, Catalytic effect, Polysulfides conversion, In-suit characterization