ZnS/MoS2 heterostructures on MXene: A strategy for improved polysulfide adsorption and conversion in Li-S batteries

The shuttle effect of polysulfides (LiPSs) and the sluggish sulfur redox kinetics are critical challenges hindering the practical application of lithium-sulfur (Li-S) batteries. This paper introduces ZnS/MoS2 heterostructures uniformly anchored on MXene (ZnS/MoS2@MXene) for use in Li-S batteries via a modified separator. The heterogeneous interface of ZnS/MoS2@MXene facilitates efficient adsorption, catalysis, and conversion of LiPSs, thereby suppressing the shuttle effect and significantly enhancing sulfur redox kinetics. The redox kinetics and the mechanism behind the enhanced chemisorption effect of ZnS/MoS2@MXene are thoroughly investigated using density functional theory (DFT) calculations. As anticipated, Li-S batteries employing ZnS/MoS2@MXene demonstrate remarkable rate performance and long-term cycling stability. The specific capacity of the ZnS/ MoS2@MXene battery reaches 1504.4 mAh g- 1 at 0.1C. The ZnS/MoS2@MXene battery retains a high discharge specific capacity of 741 mAh g- 1 after 500 cycles at 1C, with a per-cycle decay rate of just 0.067 %. Notably, with a sulfur loading of 5.6 mg cm- 2 , the areal specific capacity remains at 3.6 mAh cm-2 after 100 cycles at 0.2C. This study presents a viable strategy for developing more efficient heterostructure catalysts for Li-S batteries.