Controllable self-assembled flower-like FeS with N-doped carbon coating anchored on S-doped reduced graphene oxide as high-performance lithium-ion battery anode

Abstract

Iron sulfide (FeS) was supposed to be a suitable substitute for the commonly used graphite anode in lithium-ion batteries due to its higher specific capacity. However, its electrochemical property was severely limited due to its weak conductivity and evident volume change. To address these issues, we successfully construct controllable self-assembled flower-like with N-doped carbon coating FeS anchored on S-doped reduced graphene oxide (FeS/C@rGO) nanocomposites, used the synthesized octahedron iron-based metal-organic framework and graphene oxide composite (Fe-MOF@GO) as the precursor and thioacetamide as the sulfur via high-temperature calcination. The flower-like structure was generated by the controllable self-assembly of FeS nanosheets following an octahedral collapse, which enhanced the contact area between the active material and the electrolyte and improved Li+ transmission efficiency. Furthermore, the N-doped carbon and rGO efficiently inhibits the volume growth and aggregation of FeS nanosheets, resulting in the fabrication of controllable self-assembled flower-like FeS/C@rGO with a stable structure and outstanding rate performance. The discharge capacities of the FeS/C@rGO electrode were 1446.3, 1379.4, 1266.7, 1179.2, 1097.5 and 980.7 mAh g−1 at different current densities of 0.1, 0.2, 0.5, 1.0, 2.0 and 5.0 A g−1, respectively. When the current density returns to 0.1 A g−1, the reversible capacity is restored to 1629.7 mAh g−1. Moreover, the reversible specific capacity of FeS/C@rGO anode was 1428.2 mAh g−1 (130 cycles) at 0.1 A g−1 current density, showing excellent cycling performance.