Designing a carbon-encapsulated ZnS/SnS₂/SnO₂ heterojunction secondary battery anode displaying large capacity and...

Developing heterostructured anodes with good electrical/ionic conductivity is significant to achieve high-performance sodium-ion batteries. Here, a carbon-encapsulated hollow ZnS/SnS₂/SnO₂ heterojunction anode is developed, which exhibits excellent Na-storage performance and stability. The ZnS/SnS₂/SnO₂@C anode shows a large capacity of 612 mAh g^-1 after 100 cycles with a high coulombic efficiency. After 400 cycles at 1.0 A g^-1, capacity is retained at 471 mAh g^-1, and good temperature tolerance is also exhibited, retaining 247 mAh g^-1 after 130 cycles at -10 °C. The in situ Raman spectroscopy and in situ X-ray diffraction verified high charge-discharge reversibility, indicating that this rational design of the carbon-encapsulated hollow sulfide/oxide heterostructure could be a promising approach for developing high-performance energy-storage composites.