Lithium-modulated rod-like molybdenum disulfide as a separator coating for Li-S batteries

Lithium-sulfur (Li-S) batteries have attracted considerable attention because of their high theoretical specific capacity and energy density. However, their practical deployment remains limited by soluble lithium polysulfides (LiPSs) and the slow kinetics of sulfur redox reactions. Herein, a hydrothermal strategy is employed to obtain Li-regulated MoS 2 (Li-MoS 2 ), which is then applied as a functional coating on a polypropylene (PP) separator. The introduction of lithium chloride regulates the growth direction of MoS 2 , forming rod-like assemblies composed of nanosheets, and induces partial metallic 1T-MoS 2 . This coexisting structure enhances electron transport and offers accessible reaction sites that promote LiPSs capture and accelerate their catalytic transformation. Meanwhile, Li regulation expands the MoS 2 interlayer spacing, reduces Li + diffusion resistance, and promotes Li + migration during sulfur redox reactions. The Li-MoS 2 functional layer improves interfacial stability and suppresses LiPSs migration toward the lithium anode, thereby mitigating shuttle-induced side reactions. Consequently, the Li-MoS 2 separator enables excellent cycling stability and rate performance, retaining 503 mAh g −1 after 1000 cycles at 1C with a low capacity decay rate of 0.062% per cycle. This work demonstrates the potential of Li-modulated MoS 2 as an efficient functional separator coating for high-performance Li-S batteries.