Molybdenum Sulfides for Li-S Batteries: A Comprehensive Review of Modulation Strategies and Catalytic Chemistry.

Lithium-sulfur (Li-S) batteries have attracted significant attention as next-generation energy storage systems owing to their ultrahigh theoretical energy density and low cost. However, their practical deployment is hindered by sluggish redox kinetics, severe volume variation, and the shuttle effect of soluble LiPSs. To overcome these limitations, polar catalytic materials capable of regulating sulfur electrochemistry have been widely investigated. Among them, molybdenum-based sulfides, particularly molybdenum disulfide (MoS2), have emerged as promising candidates due to their tunable electronic structures, abundant catalytic active sites, and strong chemical affinity toward polysulfides, enabling simultaneous polysulfide confinement and catalytic conversion. This review systematically summarizes recent advances in molybdenum-based sulfides for Li-S batteries, focusing on the design principles and catalytic mechanisms of MoS2-based materials. Special attention is given to seven representative modulation strategies, including structural, support, defect, phase, doping, expansion, and heterostructure engineering. In addition, other molybdenum-based sulfides, such as amorphous MoSx and Chevrel-phase Mo6S8, are discussed. Finally, current challenges and future research directions are outlined.