Synergistic effect of dual-carbon-coated MoS2@C@SnS2-NC and locally expanded interlayer spacing on lithium storage

Abstract

The development of multicomponent composites with favorable morphology and superior architecture is crucial for designing advanced lithium-ion batteries. In this work, a MoS₂@C@SnS₂-NC material featuring a dual-carbon confinement structure and locally expanded interlayer spacing was constructed via a facile double-carbon coating process. In this multi-layered architecture, hollow MoS₂ serves as the substrate, significantly increasing the specific surface area. A robust carbon scaffold is established through dual-layer engineering: the inner carbon coating preserves tubular architecture against collapse and alleviates cycling-induced strain, while the outer carbon barrier concurrently suppresses polysulfide shuttle and reinforces structural durability, collectively ensuring electrode integrity. Furthermore, the integrated carbon network facilitates charge transport, leading to significantly enhanced electronic conductivity. During the growth of SnS₂, free dopamine molecules intercalate into the vertically aligned SnS₂ nanosheets, leading to localized expansion of the interlayer spacing. This greatly facilitates Li⁺ ion transport during charging and discharging, while the vertically aligned SnS₂ nanosheets provide abundant active sites for electrochemical reactions. Owing to its unique structural configuration, the MoS₂@C@SnS₂-NC composite retains a high reversible capacity of 1329.6 mAh g⁻¹ following 100 cycles at 0.1 A g⁻¹, delivers a substantial capacity of 647.7 mAh g⁻¹ even at 5.0 A g⁻¹, and maintains 1223.6 mAh g⁻¹ after 1000 cycles at a current density of 1 A g⁻¹. Furthermore, a MoS₂@C@SnS₂-NC//LiFePO₄ full cell was assembled to evaluate the practical application potential of the composite.