Highly Porous Fe3O4/Graphene Aerogels for Enhanced Lithium Storage

Abstract

A facile and green method was adopted to produce iron oxide/graphene composite which can be used as free-standing and additive-free electrodes in lithium-ion batteries. In the synthesis process, after graphene oxide and FeCl3 being mixed in aqueous media and subsequently being freeze-dried into the form of aerogel, FeCl3 reacts with epoxy groups on graphene oxide under N2 to from Fe3O4 nanoparticles and simultaneously reduce graphene oxide in the heat treatment, leaving behind a hierarchically porous graphene matrix on which Fe3O4 nanoparticles were uniformly dispersed. Such composite products, featured by its high porosity and homogeneous distribution of Fe3O4 nanoparticles, showed an enhancement in the electrochemical performance when used as anode materials in lithium-ion batteries. This work investigated the role of preparation parameters including the weight ratio of Fe3O4/graphene and heating temperature in affecting the electrochemical performance of as-prepared electrode. F1G2-600 presented a high reversible capacity of 1224 mAh/g at 0.1 A/g with the Coulombic efficiency of 73.8% in the first cycle. In the long-term test, F1G2-600 still delivered a remaining capacity of 573.8 mAh after 1000 cycles at 1 A/g with a retention rate of 82.8%. Therefore, this easily fabricated Fe3O4/graphene composite with high capacity and desirable durability holds promise in the scalable application as anode materials in high-power LIBs.