FeS2 microspheres wrapped by N-doped rGO from an Fe-based ionic liquid precursor for rechargeable lithium ion batteries

摘要: Earth-abundant pyrite (FeS2) is a promising anode material for lithium ion batteries (LIBs) because of its high theoretical specific capacity (894 mA h g−1). However, LIBs using pristine FeS2 usually suffer from volume expansion, dissolution polysulfides, and low conductivity Li2S. Herein, FeS2/N-doped reduced graphene oxide microspheres (FeS2/N-rGO) are first synthesized an Fe-based ionic liquid, [C12MMim]FeCl4 (C12MMim = 1-dodecyl-2,3-dimethylimidazolium), which can not only be used as the metal nitrogen source but also assembly medium surfactant. As rechargeable LIBs, as-obtained FeS2/N-rGO composites display 950 g−1 after 140 cycles at current density 150 deliver average reversible discharge 973, 867, 778, 671 0.2, 0.5, 1.0, 2.0 A g−1, respectively. Even density, still reach 510 g−1. More importantly, deep cycling, 973 recovered when to 0.2 This excellent stability outstanding rate performance mainly attributed suppression polysulfide intermediates expansion by conductive N-doped rGO matrix.