Boron and nitrogen co-doped porous carbons (BNCs) were prepared through a facile procedure using citric acid, boric acid and nitrogen as C, B and N precursors, respectively. The BNC samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and nitrogen sorption at 77 K. Cyclic voltammetry and galvanostatic charge/discharge experiments were adopted to investigate their electrochemical behaviors. The BNC-9 and BNC-15 samples with high specific surface areas of 894 and 726 m(2) g(-1) showed the large specific capacitance Lip to 268 and 173 Fg(-1), respectively, with the current of 0.1 A g(-1). When the current was set as 1 A g (1). the energy densities were 3.8 and 3.0 Wh kg(-1) and the power densities were 165 and 201 W kg (1) for BNC-9 and BNC-15, respectively. Thus, BNC-15 is more suitable to apply in high-power-demanded occasion, while BNC-9 tends to store more energy. (c) 2008 Elsevier B.V. All rights reserved.