Low crystallinity SnS encapsulated in CNTs decorated and S-doped carbon nanofibers as excellent anode material for sodium-ion batteries

As a charming alternative anode material for sodium ion batteries (SIBs), SnS possesses outstanding theoretical capacity. However, the enormous volume variation and intrinsic poor electrical conductivity hamper its further applications. In the present work, SnS/CNTs encapsulated by S doped CNFs hybrids (SnS/CNTs@S-CNFs) were synthesized through solvothermal synthesis of SnS2/CNTs precursor, followed by electrospinning and thermal treatment. During the thermal treatment, SnS2in-situ transformed to SnS through a phase transition process. Simultaneously, the SnS2 dissociation generated S atoms could dope to CNFs, which is believed to be beneficial to sodium storage performance. Thanks to the robust framework constructed by CNFs and CNTs, the as-prepared composite can be employed as free-standing anodes for SIBs. At a current density of 0.8 A g−1, a reversible capacity of 296.6 mAh g−1 can be retained after 600 cycles, corresponding to a capacity retention of 78.9%. Besides, a superior rate capability of 252.4 mAh g−1 is achieved at 3.2 A g−1. These results suggest that SnS/CNTs@S-CNFs holds great prospective as potential anode material for SIBs.