Liquid–Solid Conversion of Lithium Polysulfides Electrocatalyzed by MoS 2 Rich in Edge Active Sites in Li–S Batteries

ABSTRACT The practical application of Li–S batteries is limited by the slow kinetics of lithium polysulfides (LiPSs) conversion on the S electrode. In particular, the liquid–solid conversion of soluble LiPSs to solid Li 2 S is a key factor limiting the rate performance and cycle life of Li–S batteries. The flower‐like MoS 2 (F‐MoS 2 ) was synthesized via a hydrothermal method. Compared with bulk MoS 2 (B‐MoS 2 ), the introduction of polyvinylpyrrolidone (PVP) inhibited the layered stacking of nanosheets along the c ‐axis, expanded the interlayer spacing of the (002) plane, presented an open nanosheet structure, and exposed more abundant edge active sites. F‐MoS 2 exhibited a stronger anchoring‐conversion catalytic ability for LiPSs in the electrolyte. Benefiting from the enhanced LiPSs anchoring and catalytic conversion, the S@F‐MoS 2 cathode retained a discharge capacity of 601.3 mAh g −1 after 100 cycles at 0.1 C; in a separate rate‐capability test, it delivered 668.1 mAh g −1 at 1.6 C in the 25th cycle. This paper demonstrates a PVP‐assisted strategy to enhance the exposure of edge active sites on the catalyst of the S electrode, thereby accelerating the liquid–solid conversion step during the discharge process.