In this work, large scale ultrathin NiO nanoflakes grown on nickel foam have been successfully obtained by a facile, low cost and eco-friendly route under mild temperature. The average thickness of the as-obtained NiO nanoflakes is about 10 nm. And they possess large surface area of 89.56 m(2) g(-1) and the dominant pore size of 2.313 nm. The electrochemical properties of the obtained product were evaluated by cyclic voltammetry (CV), galvanostatic charge-discharge measurement and electrochemical impedance spectroscopy (EIS). The electrochemical tests demonstrate the highest discharge areal capacitance of 870 mF cm -2 at 1 mA cm(-2) and excellent long cycle-life stability with 84.2% of its discharge areal capacitance retention after 6000 cycles at the current density of 10 mA cm(-2). The remarkable electrochemical capacitive performance revealed NiO nanoflakes grown on nickel foam might be promising supercapacitor electrode materials for future energy storage applications. (C) 2015 Elsevier B.V. All rights reserved.