Metal Ion Cutting-Assisted Synthesis of Defect-Rich MoS₂Nanosheets for High-Rate and Ultrastable Li₂S Catalytic Deposition

Active metal ions often show a strong cutting effect on the chemical bonds during higherature thermal processes. Herein, a one-pot metal ion cutting-assisted method was adopted to design defect-rich MoS_2-xnanosheet (NS)/ZnS nanoparticle (NP) heterojunction composites on carbon nanofiber skeletons (CNF@MoS_2-x/ZnS) via a simple Ar-ambience annealing. Results show that Zn²⁺ions capture S^2-ions from MoS₂and form into ZnS NPs, and the MoS₂NSs lose S^2-ions and become MoS_2-xones. As sulfur hosts for lithium-sulfur batteries (LSBs), the CNF@MoS_2-x/ZnS-S cathodes deliver a high reversible capacity of 1233 mA h g^-1at 0.1 C and keep 944 mA h g^-1at 3 C. Moreover, the cathodes also show an extremely low decay rate of 0.012% for 900 cycles at 2 C. Series of analysis indicate that the MoS_2-xNSs significantly improve the chemisorption and catalyze the kinetic process of redox reactions of lithium polysulfides, and the heterojunctions between MoS_2-xNSs and ZnS NPs further accelerate the transport of electrons and the diffusion of Li⁺ions. Besides, the CNF@MoS_2-x/ZnS-S LSBs also show an ultralow self-discharge rate of 1.1% in voltage. This research would give some new insights for the design of defect-rich electrode materials for high-performance energy storage devices.