Nickel oxide (NiO)-based supercapacitor electrodes have attracted great attention due to the ultra-high theoretical specific capacitance. NiO, as a typical pseudocapacitive, is considered to be the most promising candidate as an electrode material for supercapacitors. Herein, the NiO nanostructures directly grown on the Ni foam have been successfully designed and synthesized via the hydrothermal method. The optimal Ni foam/NiO electrode exhibits a high specific capacity of 93.2 C/g at a current density of 5 mV/s. The enhanced electrochemical performance of Ni foam/NiO electrodes is due to the unique morphological architecture which facilitates open access and promotes electrolyte ion/electron transport. [ABSTRACT FROM AUTHOR]