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 FeCl 3 being mixed in aqueous media and subsequently being freeze-dried into the form of aerogel, FeCl 3 reacts with epoxy groups on graphene oxide under N 2 to from Fe 3 O 4 nanoparticles and simultaneously reduce graphene oxide in the heat treatment, leaving behind a hierarchically porous graphene matrix on which Fe 3 O 4 nanoparticles were uniformly dispersed. Such composite products, featured by its high porosity and homogeneous distribution of Fe 3 O 4 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 Fe 3 O 4 /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 Fe 3 O 4 /graphene composite with high capacity and desirable durability holds promise in the scalable application as anode materials in high-power LIBs.