Synthesis of FeS2/CoS heterostructure microspheres as anodes for high-performance Li-ion batteries

FeS2/CoS and FeS2/CoS/C composites were synthesized by solvothermal method and following vapor phase vulcanization at mild temperature with binary oxide CoFe2O4 as precursors. All FeS2/CoS composites prepared at different molar ratios of Fe3+ and Co2+ ions exhibit the similar morphology of solid microspheres. As anode materials for lithium-ion batteries (LIBs), the as-prepared FeS2/CoS and FeS2/CoS/C composites show higher reversible capacity and better cycling performance, compared with the bare FeS2 and CoS. Among them, the FeS2/CoS composite with molar ratio of Fe3+ and Co2+ of 2:1 exhibits the high reversible capacity of 1150 mAh g(-1) after 100 cycles at 100 mA g(-1) and even 610 mAh g(-1) at 1.0 A g(-1) after 900 cycles. This strategy for synthesizing the heterogeneous structure of binary sulfide can effectively improve the kinetic which thus enhance the electrochemical performance of materials. This work can provide an effective method and idea for the preparation and modification of FeS2 and other transition metal sulfide anode materials for LIBs in the future.

Automated summary

FeS2/CoS and FeS2/CoS/C composites were synthesized via solvothermal method and vapor phase vulcanization, using CoFe2O4 as precursors. The composites exhibited similar morphology of solid microspheres. As anode materials for LIBs, the composites showed higher reversible capacity and better cycling performance compared with bare FeS2 and CoS. The FeS2/CoS composite with a molar ratio of Fe3+ and Co2+ of 2:1 achieved a high reversible capacity of 1150 mAh g(-1) after 100 cycles at 100 mA g(-1) and even 610 mAh g(-1) at 1.0 A g(-1) after 900 cycles. This strategy of synthesizing heterogeneous binary sulfides can effectively improve the kinetics and enhance the electrochemical performance of materials. This work provides an effective method and idea for the preparation and modification of FeS2 and other transition metal sulfide anode materials for LIBs in the future.