Abstract
The development of efficient, scalable, and economically viable electrode materials with high specific capacitance is of great significance for supercapacitor applications. Herein, alpha-Fe2O3 nanoparticles, alpha-Fe2O3/rGO, and alpha-Fe2O3/ SnO2/rGO nanocomposite were synthesized by a one-step hydrothermal method. Different characterization techniques were used to study the physical and chemical properties of the prepared materials. The powder XRD measurement revealed that the formation of the ternary composite without any impurities. As characterized by SEM and TEM techniques, both alpha-Fe2O3 and SnO2 nanoparticles were embedded on two-dimensional reduced graphene oxide sheets. The electrochemical properties of the prepared electrode materials were studied by cyclic voltammetry and galvanostatic charge/discharge, and impedance spectroscopy techniques in a 6 M KOH electrolyte solution. All the electrode materials exhibit Faradic reaction peaks in CV curves which imply the pseudocapacitive nature of the prepared materials. The ternary alpha-Fe2O3/SnO2/ rGO nanocomposite demonstrated the enhanced specific capacitance of 821 Fg(-1) at 1Ag(-1) than that of alpha-Fe2O3 nanoparticles (373 Fg(-1) at 1Ag(-1)), and alpha-Fe2O3/ rGO (517 Fg(-1) at 1Ag(-1)) nanocomposite with excellent cyclic retention (98.7%) after successive 10,000 cycles. This improved electrochemical performance of ternary alpha-Fe2O3/SnO2/rGOnanocomposite is mainly attributed to the surface properties of nanostructures of metal oxides and an excellent conductive network. Moreover, the asymmetric supercapacitor (ASC) device was fabricated using the ternary alpha-Fe2O3/SnO2/rGOnanocomposite as the anode material and rGO as the cathode material. The ASC device showed an energy density of 17 Wh Kg(-1) at a power density of 3585 W kg(-1) and retains 94.52% capacitance after successive 5000 cycles at a current density of 10Ag(-1).