Dynamic interfacial anchoring in core-shell MoS₂-coated Sn anodes enables ultrastable lithium storage

While tin (Sn) is a promising high-capacity anode material for next-generation lithium-ion batteries (LIBs), its commercial viability is challenged by mechanical degradation during cycling. The significant volume expansion and consequent particle coarsening lead to premature electrochemical failure. To circumvent these challenges, we designed a hierarchical nanocomposite of molybdenum disulfide (MoS₂) coated Sn using a scalable electrospinning method followed by pyrolysis. By encapsulating Sn nanoparticles within MoS₂ nanosheets and anchoring them onto a one-dimensional carbon nanofiber (CNF) network, the nanostructure maintains intimate interfacial contact between all functional components during cycling. When evaluated as an anode for LIBs, the material demonstrates high reversible capacity, excellent rate performance, and superior cycling stability, with a capacity retention of 737 mAh g^-1 over 1400 cycles under a high current density of 3.0 A g^-1. In-depth mechanistic analysis reveals a powerful synergistic interplay: the MoS₂ shell and its conversion products (Mo and Li₂S) effectively buffer the volume expansion of the Sn core, while the metallic Sn enhances charge transfer kinetics. Theoretical calculations further confirm a strong thermodynamic preference for Sn to anchor onto Mo sites, preventing the aggregation and pulverization that typically plague Sn-based anodes. By employing nanoscale engineering to create synergistic effects, this study outlines a viable approach for developing high-performance anodes based on conversion-alloying mechanisms.