Engineering of Ni3S4/Co3S4 nanosheets@N, S co-doped carbon anode for lithium-ion batteries

Developing lithium-ion batteries (LIBs) with high electrochemical performance to meet the energy storage requirements has become a research hotspot. Transition metal sulfides (TMSs) have drawn much attention because of their long cycle life and significantly specific capacity. Herein, we synthesize the Ni3S4/Co3S4 nanosheets@N, S co-doped carbon (Ni3S4/Co3S4@NSC) composites by hydrothermal technology. Such nanosheets constituted by heterostructure and glass state of Ni3S4 and Co3S4 are beneficial to lithium-ion transport, and N, S co-doping improves electronic structure for the enhancement of electronic conductivity. Its synergetic effect delivers a high specific capacity of 1619.1 mA h g−1 at a current density of 100 mA g−1 with a stable coulombic efficiency of ∼97%. Unique 120° angle formed by assembling nanosheets on the surface of mesoporous carbon facilitates a good cycle stability (a capacity retention ratio of ∼74.3% over 100 cycles). This work provides a new strategy to regulate performance of LIB anodes.