Topotactical conversion of carbon coated Fe-based electrodes on graphene aerogels for lithium ion storage

Abstract

Iron oxides and iron sulfides have attracted significant research concerns for lithium-ion batteries (LIBs) due to their higher theoretical capacity than the commercial electrode. However, they both suffer from large volume expansion during cycling and poor electrical conductivity. Iron sulfides have another problem of the dissolution of polysulfides into organic electrolytes. This work reports a sulfur-doped graphene aerogel (GA) supported FeS₂@carbon composite with better lithium ion storage properties than its intermediate precursors (GA supported Fe–Fe₃O₄@C and Fe₂O₃). It exhibits a high reversible capacity of ∼1000 mA h g⁻¹ at 0.1 C during cycling with good rate capability. These enhanced electrochemical properties are mainly attributed to the synergetic effect of the GA support, carbon coating and sulfur doping.