Progress and development of Fe3O4 electrodes for supercapacitors

Among the electrochemical energy storage systems, supercapacitors have attracted increased attention due to their high power performance and long cycle life. Hence, they serve as a good candidate for applications where high power delivery or uptake is essential. As one of the most abundant materials on earth, magnetite (Fe3O4) is intensively studied as an electrode material for supercapacitors due to its different valence states, high theoretical specific capacitance, large potential window, low cost and eco-friendliness. This review provides an overview of the charge storage mechanism and the factors affecting the supercapacitive performance of Fe3O4. A comprehensive analysis of recent findings and ongoing research studies on Fe3O4 electrodes and their composite electrodes including carbon materials, metal oxides and conducting polymers is presented. Also, the asymmetric supercapacitor cell performances of Fe3O4 based electrodes are discussed.