Synthesis and Characterization of Ternary α-FeO/NiO/rGO Composite for High-Performance Supercapacitors.

Herein, pure α-FeO, binary α-FeO/NiO, and ternary α-FeO/NiO/rGO composites were prepared by a hydrothermal method. The properties of the prepared materials were studied by powder X-ray diffraction, scanning electron microscopy, TEM, XPS, and Brunauer-Emmett-Teller techniques. The clusters of smaller α-FeO nanoparticles (∼30 nm) along with conducting NiO was freely covered by the rGO layer sheet, which offer a higher electrode-electrolyte interface for improved electrochemical performance. The ternary composite has shown a higher specific capacitance of 747 F g@ a current density of 1 A g in a 6 M KOH solution, when compared with that of α-FeO/rGO (610 F g@1 A g) and α-FeO (440 F g@1 A g) and the nanocomposite. Moreover, the ternary α-FeO/NiO/rGO composite exhibited a 98% rate capability @ 10 A g. The exceptional electrochemical performance of ternary composites has been recognized as a result of their well-designed unique architecture, which provides a large surface area and synergistic effects among all three constituents. The asymmetric supercapacitor (ASC) device was assembled using the ternary α-FeO/NiO/rGO composite as the anode electrode (positive) material and activated carbon as the cathode (negative) material. The ASC device has an energy density of 35.38 W h kg at a power density of 558.6 W kg and retains a 94.52% capacitance after 5000 cycles at a 1 A g current density.