Three-Dimensional Nitrogen-Doped Hierarchical Porous Carbon as an Electrode for High-Performance Supercapacitors

A facile and sustainable procedure for the synthesis of nitrogen-doped hierarchical porous carbons with a three-dimensional interconnected framework (NHPC-3D) was developed. The strategy, based on a colloidal crystal-templating method, utilizes nitrogenous dopamine as the precursor due to its unique properties, including self-polymerization under mild alkaline conditions, coating onto various surfaces, a high carbonization yield, and well-preserved nitrogen doping after heat treatment. The obtained NHPC-3D possesses a high surface area of 1056 m² g^-1, a large pore volume of 2.56 cm³ g^-1, and a high nitrogen content of 8.2 wt %. The NHPC-3D is implemented as the electrode material of a supercapacitor and exhibits a specific capacitance as high as 252 F g^-1 at a current density of 2 A g^-1. The device also shows a high capacitance retention of 75.7 % at a higher current density of 20 A g^-1 in aqueous electrolyte due to a sufficient surface area for charge accommodation, reversible pseudocapacitance, and minimized ion-transport resistance, as a result of the advantageous interconnected hierarchical porous texture. These results showcase NHPC-3D as a promising candidate for electrode materials in supercapacitors.