Hemispherical nitrogen-doped carbon spheres integrated with polyindole as high performance electrode material for supercapacitor applications

Abstract

Herein we report the synthesis of ordered hemispherical N-doped carbon spheres from the ionic liquid using silica template. Doping of N is very effective in enhancing the capacitive performance of carbon by additional pseudocapacitive contribution. Further, the introduction of polyindole via in-situ oxidative polymerization of indole monomer leads to enhanced conductivity owed to the modified charge transport pathways resulting in promoted gravimetric capacitance (397 F g−1 at 1 A g−1) in case of the composite. The composite stores charge both through electric double layer mechanism and pseudocapacitive mechanism. This design leads to the attainment of balanced porosity and density leading to the enhancement in the volumetric capacitance (432 F cm−3), as well. This composite also exhibits good cyclic stability, coulombic efficiency, enhanced energy, and power density. All these results project the composite of hemispherical N-doped carbon and polyindole as a very promising supercapacitor electrode material.