Binder free heteroatom-doped graphene oxide as high energy density electrodes for supercapacitor applications

We explored the potential of heteroatom-doped graphene oxide (GO)-based electrodes for energy storage. Binder-free electrodes were synthesized using the hydrothermal method, where doping of GO and its electrode development was achieved simultaneously in one step. GO was doped with nitrogen (NGO) and boron (BGO) using urea and boric acid as nitrogen (N) and boron (B) sources, respectively. In addition, GO was also co-doped with B and N (BNGO). The atomic percentages of nitrogen and boron in NGO and BGO were found out to be 6.13% and 17.94%, respectively, as revealed by XPS. The BNGO had atomic percentages of boron and nitrogen as 23.76% and 3.64%, respectively. Electrodes were electrochemically characterized in 3 M KOH electrolyte by employing cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and galvanostatic charge-discharge (GCD). CV analysis revealed that NGO and BNGO exhibited superior charge storage capacity with a high specific capacitance of 855 and 811 F g⁻¹, respectively, at 1 m Vs⁻¹. CV data were further analyzed to identify and quantify charge storage mechanism, and it suggested that binder-free-doped electrodes exhibited diffusion-controlled charge storage as dominant behavior. Thus, our results demonstrate an approach to dope GO and develop high-performance, binder-free electrodes for supercapacitor applications in a facile single-step hydrothermal method.