Supercapacitors are attracting attention as energy storage devices but the energy density and cycle life of electrode materials require further improvement for commercial applications. To achieve this goal, a corn flake-like NiO nanostructure on nickel foam was synthesized using a facile electrodeposition method. X-ray diffraction, high resolution transmission electron microscopy, and field emission scanning electron microscopy confirmed the formation of a corn flake-like NiO nanostructure on nickel foam. The electrochemical properties of the as-prepared NiO nanostructure were analyzed by cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy. The direct formation of a highly porous corn flake-like NiO nanostructure on nickel foam provided an excellent electronic charge transfer rate with a low equivalent series resistance and good ionic accessibility for strong supercapacitive behavior. The as-prepared NiO nanostructure on nickel foam exhibited a specific capacitance of 1717 F g⁻¹ and a capacitance retention of 87% after 5000 cycles. The NiO//activated carbon asymmetric supercapacitor fabricated using a polyvinyl alcohol-KOH gel electrolyte showed high energy and power densities of 44 W h kg⁻¹ and 14 kW kg⁻¹, respectively. Overall, the corn flake-like NiO nanostructure on nickel foam is an excellent candidate for supercapacitor applications.