Preparation and application of NiS2/NiSe2 heterostructure as a sulfur host in lithium-sulfur batteries

Abstract

The introduction of heterostructure in the cathode material of Li-S battery is an effective method to improve the redox reaction kinetics and suppress the shuttle effect of polysulfide. A metal sulfide/metal selenide (NiS2/NiSe2) heterostructure with hollow tetrahedral structure is prepared as a sulfur host of lithium-sulfur batteries. The prepared NiS2/NiSe2 heterostructure exhibits efficient charge transfer at the heterojunction interface, thereby enhancing catalytic activity for redox reactions of polysulfides and facilitating their rapid conversion. Moreover, the unique hollow tetrahedral structure, along with abundant surface pores, enables high sulfur loading capacity, providing abundant electrochemical reaction sites to enhance sulfur utilization efficiency. The results demonstrate that the NiS2/NiSe2 heterostructure material exhibits a remarkable initial capacity of 1338.9 mAh/g at 0.2 C, along with exceptional cycling stability (maintaining a capacity of 517.6 mAh/g after 200 cycles at 0.2 C, with only a negligible decay rate of 0.3% per cycle, retaining a capacity of 462.6 mAh/g after 500 cycles at 1 C, with an insignificant decay rate of merely 0.12% per cycle). The facile preparation of this NiS2/NiSe2 heterostructure not only enables the realization of lithium-sulfur batteries with exceptional capacity, but also opens up broader avenues for exploring high-performance heterogeneous materials.