Facile synthesis of yolk-shell CoS2@FeS2@NC hollow microspheres for advanced lithium-ion batteries anode materials

Transition metal chalcogenides (TMCs) are considered to be promising as anode materials for lithium-ion batteries (LIBs) due to their unique physical and chemical properties and high theoretical specific capacity. Nevertheless, the poor rate performance and fast capacity decay seriously affect its practical application in LIBs. In the present study, porous yolk-shell CoS2@FeS2@NC hollow microspheres have been successfully prepared through a simple step-by-step strategy. In addition to shortening the transport length of lithium ions, this unique structure can also successfully alleviate the volume change during charging/discharging. Importantly, the coating of the nitrogen-doped carbon (NC) layer effectively enhances the electrical conductivity of the material and prevents exfoliation of metal particles. The yolk-shell CoS2@FeS2@NC hollow microspheres show high specific capacity (1162.6 mAh g−1) and excellent cycle stability (614 mAh g−1 at 1 A g−1 after 100 cycles) when used as anode material for LIBs. These fascinating electrochemical performances strongly demonstrate that the as-obtained yolk-shell CoS2@FeS2@NC hollow microspheres can be highly applicable in the field of high-performance LIBs electrode materials.