3D carbon-coated stannous sulfide-molybdenum disulfide anodes for advanced lithium-ion batteries

Abstract

Metal sulfides have been extensively studied as alternative anodes for lithium-ion batteries (LIBs) due to their high specific capacity, which comes from their combined conversion and alloying/de-alloying reactions with lithium, forming Li₂S and corresponding lithium alloys, respectively. However, the large volume fluctuation during cycling, low electronic/ionic conductivities of both metal sulfides and Li₂S, and the electrochemical inactivity of Li₂S lead to poor reversibility and stability. Here, we report a facile way to synthesize a three-dimensional carbon-coated stannous sulfide-molybdenum disulfide composite (3D SnS–MoS₂@C) which is proposed to alleviate the aforementioned problems. 3D SnS–MoS₂@C exhibits a highly porous structure, which enhances the contact between the electrode and the electrolyte, promotes the transport of both electrons and Li⁺, and buffers the volume change during cycling. MoS₂ contributes to the specific capacity and catalyzes the oxidation of Li₂S. The 3D SnS–MoS₂@C anode demonstrates a capacity of 887.1 mA h g⁻¹ for the first cycle at 200 mA g⁻¹ and achieves a capacity retention of 97.1% over 200 cycles. In addition, the ternary composite exhibits a superior rate performance and cycling lifespan, achieving a gravimetric capacity of 651.2 mA h g⁻¹ at 1000 mA g⁻¹ after 500 cycles. The proposed facile and effective strategy could be universally applied to other metal sulfide-based electrodes.