Abstract:
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 ID/IG 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.
