Watermelon Flesh‐Like Ni₃S₂@C Composite Separator with Polysulfide Shuttle Inhibition for High‐Performance Lithium‐Sulfur Batteries

Abstract The shuttle effect limits the practical application of lithium‐sulfur (Li‐S) batteries with high specific capacity and cheap price. Herein, a three‐dimensional carbon substrate containing Ni₃S₂nanoparticles is created to modify the separator. The in situ optical visualization battery proves that the material can realize the rapid conversion of Li₂S₆. Moreover, the impact of lithium‐ion diffusion on the reactions in the cell is investigated, and the mechanism of Ni₃S₂@C in the cell is proposed based on the “adsorption‐diffusion‐conversion” mechanism. The “adsorption‐diffusion‐conversion” process of polysulfide is carried out on the surface of the composite separator, showing positive effects on the inhibition of polysulfide shuttle and the promotion of conversion. The separator is modified to improve sulfur utilization and reduce dead sulfur accumulation through a strategy of chemical immobilization and physical blocking. This helps to bridge the existing gaps of Li‐S batteries.