As a promising alternative to lithium-ion batteries (LIBs), rechargeable sodium-ion batteries (SIBs) are attracting enormous attention due to the abundance of sodium. However, the lack of high-performance sodium anode materials limits the commercialization of SIBs. In this work, the dual enhancement of SnS2/graphene anodes in sodium storage is achieved through S-compositing and Co doping via an innovative one-step hydrothermal reaction at a relatively low temperature of 120 °C. The as-prepared 7% Co-SnS2/S@r-G composite consisting of 15.4 wt % S and 1.49 atom % Co shows both superior cycling stability (over 1000 cycles) and rate capability, giving high reversible specific capacities of 878, 608, and 470 mAh g-1 at 0.2, 5, and 10 A g-1, respectively. More encouragingly, the full-cell also exhibits an outstanding long-term cycling performance under 0.5 A g-1, which delivers a reversible capacity of 500 mAh g-1 over 200 cycles and still retains a high reversible capacity of 432 mAh g-1 over 400 cycles. The enhancement mechanism is attributed to the favorable three-dimensional structure of the composite, Co doping, and S-composition, which can induce a synergistic effect.
Keywords: Co doping, dual enhancement; SnS2; anodes; graphene, S-composites; sodium-ion batteries; transition metal sulfides.