Preparation of high capacity Sn₂S₃/Sn₃S₄/FeS/Fe₇S₈ heterostructure composite lithium-ion battery anodes from reducing agents Fe and tin-based sulfides

Tin-based sulfides, such as SnS₂, have garnered attention as lithium-ion anode materials due to their layer structure and high conductivity capacity. However, during the lithium alloying/dealloying cycles, SnS₂ material exhibits a rapid capacity decay due to the volume expansion, which hinders the application of SnS₂. In this study, a heterostructure composite material anchored on exfoliated graphite, designated as nano SnS₂S₃/Sn₃S₄/FeS/Fe₇S₈ anchored on 15.0 wt% exfoliated graphite (FSS/G-15%), was synthesized by heating a mixture of inexpensive reducing agent Fe powder and SnS₂ powder, followed by ball milling with 15.0 wt% commercial graphite. Experimental results demonstrated that FSS/G-15% had exhibited optimal overall Li⁺ storage performance, achieving approximately 1306.7, 1199.2, 1033.1, 882.3, 707.3, 507, 366.3, 255.6, and 203.5 mA hg⁻¹ at current densities of 0.1, 0.2, 0.5, 1, 2, 4, 6, 8, and 10 Ag⁻¹, respectively, surpassing the majority of SnS₂-based anode materials. The simplicity and efficiency of the synthetic method may have potential implications in various fields in the future.