Critical Roles of Heterogeneous Electrocatalysts for Advanced Lithium–Sulfur Batteries

Lithium-sulfur (Li-S) batteries are gaining attention due to their high theoretical energy density, cost-effectiveness, and environmental friendliness. However, issues such as the polysulfide shuttle effect and sluggish redox kinetics lead to low sulfur utilization efficiency and poor cycling lifespan, hindering their commercial viability. Heterogeneous catalysts have become essential for regulating sulfur in high-performance Li-S batteries. This review starts by reviewing the fundamental mechanisms involved in the redox reactions of sulfur species. The critical roles of heterogeneous catalysts in sulfur modulation are then discussed, including their ability of relieving the shuttle effect and facilitating catalytic conversions by summarizing the recent theoretical explorations and experimental findings based on various advanced characterization techniques. Additionally, the existing challenges in the field are summarized and strategic directions are proposed for heterogeneous electrocatalysts in future research on Li-S batteries. This review aims to inspire innovative designs of catalysts for the next-generation Li-S batteries.