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

A 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-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-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 of1086 mAh g(-1)at1 Cwith3.0 mg cm(-2)sulfur loading and show capacity decay of0.04 %per cycle after1500 cycles. In contrast, the Li-S batteries without interlayer merely maintain the discharge capacities of423 mAh g(-1)at1 Cwith3.0 mg cm(-2)sulfur loading and show severe capacity decay (0.12 %) after505cycles. 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.