Hierarchical NiO Nanoflake Arrays on Nickel Foam as a Supercapacitor Electrode with High Capacitance and High Rate Capability

In this paper, we report a simple and cost-effective method for fabricating hierarchical NiO nanoflake arrays on nickel foam. X-ray diffraction, scanning electron microscope and transmission electron microscope are employed to study the morphology and structure of the as-synthesized NiO materials. Galvanostatic charge/discharge measurements demonstrate that the hierarchical NiO nanocomposite displays excellent capacitive behavior between the potential range of −0.1–0.5 V, and a maximum specific capacitance as high as 823 F g −1 can be achieved at a charge/discharge current density of 4 A g −1 , and it only decreases by 20% when the current density increases to 12 A g −1 . The remarkable electrochemical performance of this hierarchical NiO nanocomposite indicates the great application potential in supercapacitors.