Facile Hydrothermal Synthesis of Boron and Nitrogen-Doped RGO as Electrode Material for Supercapacitors

The reduced graphene oxide (RGO) is a well-known material that has magnificent capacitive properties. Herein, we report the boron and nitrogen-doped RGO synthesized by hydrothermal route as an electrode material for symmetric and asymmetric supercapacitor devices. Physicochemical characterization is performed by X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy, while electrochemical characterization is performed by cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy. The specific capacitances of RGO, B-RGO, and N-RGO, as evaluated by performing CV in a three-electrode setup (scan rate of 10 mV/s) are 212.8, 317.4 and 429.5 F/g, respectively. The charge-transfer resistance of B-RGO and N-RGO are respectively 1.8 and 2.5 times lower than RGO, indicating the improved conductivity of RGO upon boron and nitrogen doping. Symmetric supercapacitor devices are fabricated using RGO as anode and B-RGO and N-RGO as a cathode. The specific capacitance of RGO//N-RGO and RGO//B-RGO devices at a current density of 0.5 A/g are 50.5 F/g and 133.2 F/g, respectively. The energy and power densities of RGO//B-RGO device at 0.5 A/g are 18.5 Wh kg−1 and 69.4 W kg−1, whereas RGO//N-RGO possess 7.0 Wh kg−1 and 69.0 W kg−1 respectively. The RGO//B-RGO device exhibited good stability, as it retained 56.3% of specific capacitance until 2000 cycles.