Synthesis and Characterization of Ternary α-Fe(2)O(3)/NiO/rGO Composite for High-Performance Supercapacitors

[Image: see text] Herein, pure α-Fe(2)O(3), binary α-Fe(2)O(3)/NiO, and ternary α-Fe(2)O(3)/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-Fe(2)O(3) 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(–1)@ a current density of 1 A g(–1) in a 6 M KOH solution, when compared with that of α-Fe(2)O(3)/rGO (610 F g(–1)@1 A g(–1)) and α-Fe(2)O(3) (440 F g(–1)@1 A g(–1)) and the nanocomposite. Moreover, the ternary α-Fe(2)O(3)/NiO/rGO composite exhibited a 98% rate capability @ 10 A g(–1). 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-Fe(2)O(3)/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(–1) at a power density of 558.6 W kg(–1) and retains a 94.52% capacitance after 5000 cycles at a 1 A g(–1) current density.