Multifunctional Cathodic Interlayer with Polysulfide Immobilization Mechanism for High‐Performance Li‐S Batteries

Abstract A highly efficient multifunctional polyvinylidene fluoride // carbon‐molybdenum disulfide (PVDF // C‐MoS 2 ) interlayer is developed by direct deposition on sulfur cathode through facile slide coating method for Li−S batteries. The as‐developed PVDF // C–MoS 2 interlayer exhibits the polysulfide adsorption and trapping capabilities, which reduces the shuttling effects and also slows down the self‐discharge in Li−S batteries. The first composite layer (C‐MoS 2 ) on the cathode maximizes the level of lithium polysulfide adsorption owing to the strong dipolar interaction of Mo−S on the polarized surface of polysulfide species. Moreover, the PVDF layer physically traps/capture the remaining polysulfide species with its interconnected microstructure for the reutilization as active material in the cathode. The Li−S batteries based on interlayers deliver the discharge capacity of 1086   mAh   g −1 at 1   C with 3.0   mg cm −2 sulfur loading and show capacity decay of 0.04   % per cycle after 1500  cycles. In contrast, the Li−S batteries without interlayer merely maintain the discharge capacities of 423   mAh   g −1 at 1   C with 3.0   mg cm −2 sulfur loading and show severe capacity decay ( 0.12   % ) after 505 cycles. The Li−S batteries also depict the remarkable cyclic performances with as‐developed interlayer for high sulfur loading cathodes and efficiently slowdowns the self‐discharge even after resting for a long time.