Supercapacitors (SCs) have long service lifetime, fast charge-discharge processes, green environmental protection and high energy efficiency.Due to these advantages, SCs have been widely employed in the power back-up systems, public transportation and medical devices, erc [1].SCs are generally of two varieties based on the charge storage mechanism:electrochemical double-layer capacitor and pseudocapacitors.The former can store charge electrostatically using reversible adsorption of ions of electrolyte onto active materials (such us carbon-based materials) [2].The latter use the fast reversible redox reaction at the surface of active materials (such us metal oxides/hydroxides and conducting polymers) [3].In contrast to the former,materials with pseudocapacitive nature have gained much attention due to their higher specific capacitance and energy density [4].To date, various transition metal oxides have been extensively studied as possible electrode materials for SCs, including RuO2, CoOx,NiO, MnO2 and MoO2 [5].Among them, Co3O4 has been studied extensively for supercapacitor applications, but less attention has been paid to micro/nano-structured cobalt monoxide (CoO), which are hard to synthesize because of the special requirements necessary to force cobalt in a low oxidation state under common ambient conditions and unavoided introductions of impurities [6].