Hollow ZnS-SnS2@MoS2 Heterostructures for High-Efficiency Adsorption-Storage- Catalysis of Polysulfides in Lithium-Sulfur Batteries

Abstract

Heterostructure catalysts show promise in facilitating the conversion between sulfur, soluble polysulfides, and solid Li₂S₂/Li₂S in Li-S batteries due to their rapid electron/ion transfer properties. However, most catalysts lack sufficient specific surface area and high catalytic activity to achieve timely adsorption and catalysis of polysulfides. Herein, hollow ZnS-SnS₂@MoS₂ heterostructures are firstly synthesized, which combine the strong absorption capacity with high catalytic activity to ensure a remarkable electrochemical performance. The hollow ZnS-SnS₂ heterogeneous cubes serve as a highly active component with an extraordinary bidirectional electrocatalytic capability for polysulfide conversion. Additionally, ultrathin MoS₂ nanosheets with large specific surface areas are coated on the ZnS-SnS₂ cubes to enhance polysulfide absorption and eliminate concentration overpotential. The hollow space in ZnS-SnS₂@MoS₂ heterostructures acts as a reservoir for sulfur and intermediate polysulfides, effectively suppressing the shuttle effect. With these advantages, the ZnS-SnS₂@MoS₂ heterostructures exhibit a synergistic adsorption-storage-catalysis effect for polysulfides. Consequently, the Li-S batteries assembled with the ZnS-SnS₂@MoS₂-modified separators demonstrate superior electrochemical performance, with a high initial discharge capacity of 1571.3 mAh g⁻¹ at 0.1 C and a low decay of 0.026% per cycle after 500 cycles at 2 C. This work provides new insight for designing high-performance electrocatalytic materials for Li-S batteries.