Heterojunction engineering and ether-based electrolyte boost In₂S₃/MoS₂ for high-efficient sodium storage

To position transition metal sulfides to function effectively as anodes in sodium-ion batteries (SIBs), it is essential to address their poor sodium storage performance, which stems from low conductivity and substantial volume fluctuations. Inspired by the heterojunction engineering, herein, a composite of In₂S₃/MoS₂ heterostructure in three-dimensional N-doped carbon frameworks (In₂S₃/MoS₂@NC) was constructed via an efficient chemical foaming and subsequent sulfuration strategy. The In₂S₃/MoS₂ heterostructure could effectively accelerate the charge transfer, augment the pseudocapacitive contribution and enhance Na⁺ adsorption ability. The system employs a glyme-based electrolyte, which helps generate a thin, stable solid-electrolyte interface. Synchronously, the N-doped carbon frameworks serve to buffer the volume variation of In₂S₃/MoS₂ by functioning as a shielding layer. As anticipated, the In₂S₃/MoS₂@NC electrode displays superior high-rate performance (243.2 mAh g^-1 at 10 A g^-1) and long-term cycling stability (352.3 mAh g^-1 at 1 A g^-1 after 1000 cycles, 223.1 mAh g^-1 at 5 A g^-1 and 170.5 mAh g^-1 at 10 A g^-1 after 2000 cycles). Particularly, it also shows potential in cryogenic applications (266.5 mAh g^-1 after 70 cycles at 0.5 A g^-1, as well as 185.9 mAh g^-1 at 2 A g^-1). By proposing a straightforward strategy to rationally design anodes for SIBs, this work further advances the understanding of heterojunction engineering and ether-based electrolytes for transition metal sulfides.