Encapsulating SnS2 nanosheets into hollow carbon sphere: A yolk-shell SnS2@C composite with enhanced sodium storage performance

Highlights: • A unique yolk-shell SnS₂@C composite with SnS₂ nanosheets encapsulated within hollow carbon spheres is synthesized. • It delivers superior sodium storage performance with high specific capacity, good cyclability, and excellent rate performance. • The unique structure with SnS₂ nanosheet, interior void space, and carbon coating accounts for its superior performance. In this study, a yolk-shell structured SnS₂@C composite is rationally synthesized through a sulfuration treatment of hollow SnO₂@C composite. The unique structure with SnS₂ nanosheets (a thickness of 15 nm) encapsulated within hollow carbon spheres (∼400 nm) is confirmed through SEM, TEM, XRD and XPS characterizations. As an anode material for sodium-ion batteries, as-synthesized SnS₂@C composite shows superior sodium storage performance. It delivers good cycling stability with a capacity of 690 mA h g⁻¹ sustained after 100 cycles at 0.1 A g⁻¹. Even at a high rate of 10 A g⁻¹, an impressive rate capability of 310 mA h g⁻¹ is still obtained. The excellent performance of this SnS₂@C composite could be attributed to its unique architecture to provide good electrical conductivity, shorten the diffusion path, tolerate the volume fluctuation, prevent the aggregation, and enhance the structure stability during cycles.