Heterostructured FeS2/SnS2 nanoparticles anchored on graphene for advanced lithium and sodium-ion batteries

Abstract

SnS2 is intensively investigated as a prospective anode for lithium and sodium-ion batteries (LIBs and SIBs), owing to its high capacity, large interlayer distance, and low redox potentials. Nevertheless, the dramatic volume variation, and inferior electrical conductivity upon discharge/charge process, resulted in poor cycling and rate performance. Herein, a heterostructured binary sulfide (FeS2/SnS2) nanoparticles coated with N-doped carbon and further wrapped with graphene (FSS@NC/rGO) is synthesized by a facile co-precipitation method coupled with PDA coating and in-situ sulfidation process. The heterostructure FeS2/SnS2 greatly accelerates the ion/electron transport, as well as keeps a stable structure during the cycling process. Meanwhile, the N-doped carbon and graphene matrix enable good electrical conductivity, as well as accommodate the volume variation during the cycling process. Accordingly, the FSS@NC/rGO displays a fantastic capacity (1192.2 mAh/g at 0.2 A/g), outstanding rate performance (499.5 mAh/g at 5.0 A/g), and long-cycle stability (724.9 mAh/g at 2 A/g after 500 loops) in LIBs. Meanwhile, the FSS@NC/rGO delivers a high Na-storage capacity of 451.8 mAh/g after 200 loops at 0.2 A/g.