In-situ activator-induced evolution of morphology on carbon materials for supercapacitors

Carbonaceous materials with diverse morphologies have shown unique and excellent performance in many fields, such as catalysis, adsorption, separation and energy storage. However, regulating the structural changes of these morphologies accurately using simple approaches is a difficult process. In this study, porous carbon materials with a morphology that changed from carbon spindles to fold-carbon spheres and then to regular carbon spheres were prepared assisted by in-situ activator of KNO₃ in co-assembly of resorcinol/phenol resin and 1-alkyl-3-methylimidazolium bromide. The activation of KNO₃ greatly improves the hydrophily, pore volume and surface area of the inert carbon skeleton, and increases heteroatom defects for the carbon framework. As electrode materials of supercapacitors, the influence of different structures on energy storage performance was studied. The obtained fold-carbon spheres showed a higher capacitance (405 F g^-1) than flake, spindle and spherical porous carbon, which is due to convenient electrolyte transmission and completely available active sites.