Boron and nitrogen co-doped porous carbon and its enhanced properties as supercapacitor

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 m² g^-1 showed the large specific capacitance up to 268 and 173 F g^-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.