Deciphering the Structural, Textural, and Electrochemical Properties of Activated BN-Doped Spherical Carbons

In this study, the effect of K₂CO₃ activation on the structural, textural, and electrochemical properties of carbon spheres (CSs) and boron and nitrogen co-doped carbon spheres (BN-CSs) was evaluated. Activation of the CSs and BN-CSs by K₂CO₃ resulted in increased specific surface areas and I_D/I_G ratios. From the X-ray photoelectron spectroscopy (XPS) results, the BN-CSs comprised of 64% pyridinic-N, 24% pyrrolic-N and 7% graphitic-N whereas the activated BN-CSs had 19% pyridinic-N, 40% pyrrolic-N and 22% graphitic-N displaying the effect of activation on the type of N configurations in BN-CSs. A possible BN-co-doping and activation mechanism for the BN-CSs is proposed. Electrochemical analysis of the electrode materials revealed that BN doping, carbon morphology, structure, and porosity played a crucial role in enhancing the capacitive behavior of the CSs. As a proof of concept, a symmetric device comprising the activated BN-CSs displayed a specific power of 800 W kg^-1 at a specific current of 1 A g^-1 within an operating cell potential of 1.6 V in a 3 M KNO₃ electrolyte. The study illustrated for the first time the role of K₂CO₃ activation in influencing the physical and surface properties of template-free activated BN-CSs as potential electrode materials for energy storage systems.