FeS₂/CuFeS₂ Composite Anodes Based on Seafloor Massive Sulfides Compositions for Lithium-Ion Batteries

Transition metal sulfides are promising anode materials for lithium-ion batteries, but their practical application is limited by severe volume variation and sluggish reaction kinetics during cycling. Inspired by the natural mineral assemblage of seafloor massive sulfides (SMS), FeS₂/CuFeS₂ composite anodes were prepared by a mechanochemical ball-milling method with mass ratios of 9:1 and 7:3 to reflect the major compositional characteristics of SMS. Among them, the 9:1 composite (F9C1) exhibited the best overall electrochemical performance, delivering a reversible capacity of 763.4 mAh g^-1 after 300 cycles at 1 C and retaining 46% of its baseline capacity at 5 C. Structural and electrochemical analyses suggested that the introduction of a small amount of CuFeS₂ likely promoted interfacial interactions between FeS₂ and CuFeS₂ phases, reduced charge-transfer resistance, and enhanced pseudocapacitive contribution, while preserving the capacity advantage of the FeS₂ host phase. These results demonstrate that mineral-inspired compositional design is an effective strategy for improving the lithium-storage performance of sulfide anodes and provides a feasible route for developing electrode materials inspired by naturally coexisting sulfide minerals.