Synergistic Effect of VS2/MoS2 as an Electrocatalyst for Accelerating Polysulfide Conversion in Lithium–Sulfur Batteries

The shuttle effect of soluble lithium polysulfides (LiPSs) poses a formidable challenge that severely compromises the electrochemical performance of lithium-sulfur (Li-S) batteries. This study introduces a unique lamellar stacked VS2/MoS2 nanoflower structure, prepared using a simple one-step hydrothermal synthesis method, to reduce the polysulfide shuttle effect in Li-S batteries. VS2/MoS2 synergistically boosts LiPS conversion, combining VS2's high conductivity with the catalytic activity of MoS2, as confirmed by density functional theory (DFT) calculations. Electrochemical testing demonstrated excellent performance for VS2/MoS2@S cathodes. It delivers an initial discharge-specific capacity of 1353 mAh g-1 at 0.1 C, and at 1 C, the capacity remains as high as 925 mAh g-1. At 0.2 C, the initial discharge-specific capacity is 1299 mAh g-1, and the capacity retention rate reaches 55% after 500 cycles. This study provides valuable insights into designing and engineering high-performance heterostructures to enhance the adsorption of LiPSs and improve the reaction kinetics in Li-S batteries.