Hydrothermal synthesis of Fe₃O₄/RGO composites and investigation of electrochemical performances for energy storage applications

Highly porous nano-structured Fe₃O₄ particles were successfully prepared on the surface of reduced graphene oxide (RGO) sheets through a one-step hydrothermal method. X-ray diffraction (XRD) and field emission scanning electron microscopy analysis (FE-SEM) confirmed not only the size and porous nature but also the formation of Fe₃O₄ and Fe₂O₃-based composites. XRD, FE-SEM and transmission electron microscopy showed the highly crystalline nature of the particles. The reduction of graphene oxide and the formation of a few layers of RGO were confirmed by Raman spectroscopy and X-ray photoelectron spectroscopy analysis. Electrochemical performances of the Fe₃O₄/RGO composite were evaluated with two electrode configurations using nickel foam as a material support as well as a current collector. The synergistic effect of RGO and the metal oxide were demonstrated in terms of enhanced energy and power density, excellent electrochemical cyclic stability and low IR drop. The specific capacitance of the Fe₃O₄/RGO composite was found to be ∼782 F g^-1 at a current density of 3 A g^-1. The improved electrical conductivity, nanometer scale particle dimension and formation of hierarchical networks with effective redox activity contributed to a remarkable supercapacitor performance.