Enhanced polysulfide regulation of lithium-sulfur batteries by ZnS-SnO₂ nano-heterostructures

Lithium-sulfur (Li-S) battery is recognized as the most promising next-generation energy storage system due to its high theoretical capacity and energy density. However, the shuttle effect of lithium polysulfides (LiPSs) and the sluggish electrochemical reaction kinetics severely hinder its practical application. In this study, a hierarchical porous carbon (HPC) conductive framework loaded with ZnS-SnO2 heterostructures (ZnS-SnO2/HPC) in situ was designed for application in Li-S batteries. The ZnS-SnO2/HPC combines the advantages of physical confinement, chemical anchoring, and rapid electron/ion migration to inhibit the shuttling of LiPSs while ensuring its rapid conversion, achieving effective regulation of the electrochemical behavior of LiPSs. The obtained lithium-sulfur battery has significantly improved electrochemical properties: high reversible capacity (868.2 mAh g-1 after 100 cycles at 0.2 C), excellent rate capacity (841.5 mAh g-1 at 3 C), and low self-discharge capacity loss (97% capacity retention after 5 days of standing). In addition, the synergistic effect also helps to improve the cycle stability, with a capacity fading rate of only 0.079% per cycle over 500 cycles at 1 C.