Molecular engineering of supercapacitor electrodes with monodispersed N-doped carbon nanoporous spheres

Abstract

Herein, a novel polytriazine compound was designed and used as a precursor for the synthesis of high nitrogen-doped porous carbon spheres (N-doped carbon-PNSs) by direct carbonization-activation; the process was simple and based on the template-free polycondensation of 2,6-diaminopyridine and formaldehyde in an aqueous solution. Moreover, by varying the 2,6-diaminopyridine to formaldehyde ratio and total monomer concentration during the synthesis of the polymeric precursor, the size of the polytriazine nanospheres could be tuned from 102 to 3900 nm with a uniform spherical geometry. After pyrolysis, the N-doped carbon-PNSs had an average N content of 8.7–10.4 wt% and surface areas of 627.8–924.4 m² g⁻¹; most importantly, the N-doped carbon-PNSs as high energy supercapacitor electrodes exhibited excellent cyclability and high specific capacitance, ramping up to 424 F g⁻¹ at 1 A g⁻¹ in 6 M KOH.