Polymerization-Pyrolysis-Derived Hierarchical Nitrogen-Doped Porous Carbon for Energetic Capacitive Energy Storage

Nitrogen-doped porous carbons are attractive electrode materials for supercapacitors because of their high specific capacitance and desirable surface property. Here, we report a facile polymerization-pyrolysis strategy to construct hierarchical porous carbon, which is rich in surface redox nitrogen species. The polymeric precursor of phenolic resin cross-linked with polyaniline is produced by a mild hydrothermal process. The following calcination procedure yields hierarchical nitrogen-doped porous carbon, which presents a large specific surface area of 968.5 m 2 g –1 with multi-scale porous structures including micro-, meso-, and macropores. It is found that pyrrolic nitrogen and oxidized nitrogen are successfully introduced on the porous carbon surface, and they can supply extra pseudo-capacitance. The synergy of massive charge storage sites and interconnected ion transport channels enables the hierarchical nitrogen-doped porous carbon to exhibit a high specific capacitance of 320.6 and 250.0 F g –1 in the alkaline electrolyte at current densities of 0.5 and 100 A g –1, respectively. In addition, the assembled symmetrical supercapacitor with organic electrolytes shows a huge energy density of 48.9 Wh kg –1 at a power density of 375.0 W kg –1, with a capacitance retention close to 100% after 50,000 cycles.