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

Abstract

AbstractA highly efficient multifunctional polyvinylidene fluoride//carbon‐molybdenum disulfide (PVDF//C‐MoS2) interlayer is developed by direct deposition on sulfur cathode through facile slide coating method for Li−S batteries. The as‐developed PVDF//C–MoS2 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‐MoS2) 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.