Electrochemical performance of SnS-SnS2@CNTs composites as anode materials for Sodium ion batteries

•SnS-SnS2@CNTs composite materials were prepared by a simple one-step solvothermal method.•The SnS-SnS2 heterostructures have a special internal electric field that promotes charge transfer.•The embedding of carbon nanotubes (CNTs) improves the anode conductivity and alleviates large volume expansion.•SnS-SnS2@CNTs exhibits a discharge capacity of 413 mAh·g−1 after 50 cycles. Tin sulfide based materials are attracting attention because of excellent performance as SIBs anode. However, SnS and SnS2 suffer from severe capacity degradation during the charge/discharge process, as well as high volume expansion, which prevents superior cycling stability of SIBs. In this work, carbon nanotubes (CNTs) modified SnS-SnS2 materials were prepared by a facile one-step solvothermal approach. The constructed SnS-SnS2 heterostructures have a special internal electric field that promotes charge transfer. The combination of CNTs also prevents agglomeration of active particles and improves the capacity and cycling durability of SIBs (413 mAh·g−1 after 50 cycles).