We demonstrate a facile, scalable and tunable method to produce a composite material based on graphene multilayers and Fe2O3, combining the good conductivity and 2D layered structure of the former and the lithium storage capacity of the latter. The composite was obtained directly from bulk graphite, exploiting the fast electrochemical intercalation of tetrachloroferrate (III) anions (FeCl4 −) and nitromethane molecules between the graphene sheets. Then, irradiation with microwaves triggered the simultaneous exfoliation of graphite and its functionalization with Fe2O3 nanocrystals, produced by the thermal hydrolysis of the FeCl4 −. This process was monitored in real time using thermal gravimetry and mass spectrometry. X-rays diffraction, Raman spectroscopy, scanning electron and transmission microscopies confirmed the final structure of the composite formed by conductive 2D nanosheets coated by Fe2O3 crystals, featuring both high crystallinity and nanometric size. The composite could be used directly as an anode in Li-ion batteries, demonstrating the viability of this approach for high yield and scalable production of graphene/metal oxide composites.