Amorphous carbon-anchored SnS2 microspheres constructed from ultrathin nanosheets for high initial coulombic efficiency anodes in sodium-ion batteries

SnS 2 has attracted widespread research attention as an anode material for sodium-ion batteries (SIBs) because of its excellent theoretical specific capacity. Unfortunately, its practical application is hindered by its inherently low conductivity, substantial volume expansion during cycling, and particularly the unsatisfactory initial Coulombic efficiency (ICE). Here, carbon particles from walnut shells were anchored onto SnS 2 microspheres composed of interwoven nanosheets via a one-step hydrothermal method to synthesize SnS 2 /C composites. C particles on the surface of SnS 2 microspheres can effectively mitigate structural degradation caused by volume expansion during (dis)charge cycles. The incorporation of amorphous C helps maintain the structural integrity of SnS 2 and facilitates the formation of a stable solid electrolyte interphase (SEI) film. Furthermore, it reduces the binding energy between Sn and Na 2 S, thereby enhancing the reversibility of SnS 2 regeneration during the charging process. In addition, carbon particles suppress the sulfur shuttle effect through both chemical and physical interactions. Consequently, the synthesized SnS 2 /C composite demonstrates a substantial specific capacity of 621.2 mAh g -1 along with an enhanced ICE of 88.4 % at 0.1 A g -1 . Moreover, it exhibits an excellent cycling stability, retaining a specific capacity of 432.9 mAh g -1 after 950 cycles at 2.0 A g -1 . The enhanced Na + storage capability of SnS 2 /C anode contributes to the outstanding rate performance and cycling durability of constructed SIB full cell, indicating its promising applicability in high-performance practical scenarios.