Camellia Pollen-Derived Carbon with Controllable N Content for High-Performance Supercapacitors by Ammonium Chloride Activation and Dual N-Doping

Graphical An integrated carbonization, activation, and nitrogen-doped process is applied to fabricate hierarchical porous carbon materials with controllable N content as electrode for supercapacitors. The symmetric supercapacitor delivers an energy density of 13.3 W h kg −1 (6 KOH) and 20 W h kg −1 (1 M Na 2 SO 4 ). Biomass-derived carbon materials are an amazing electrode material for supercapacitor, owing to their abundant, porous structure and composition. Herein, a controllable N content carbon material with hierarchical porous structure was fabricated via an integrated carbonization, activation and nitrogen-doping process. N-rich camellia pollen is used as carbon precursor, while NH 4 Cl is employed as both activation agent and dopant. The optimal N-doped carbon with higher N content (3.82 at%), suitable pore size distribution and larger specific surface area (810 m 2 g −1 ), provides abundant ion transport channels and exposes more accessible active sites. Thus, a high specific capacitance of 280 F g −1 (1 A g −1 ) in 6 M KOH (three-electrode system) can be obtained with making full use of N−HPC-1. Moreover, the assembled symmetrical supercapacitor delivers high energy densities both in 6 M KOH (13.3 Wh kg −1 ) and 1 M Na 2 SO 4 (20 Wh kg −1 ) that can be used for LED lighting. More than that, it is also demonstrates excellent cycle stability in 6 M KOH (85.4% after 20000 cycles at 20 A g −1 ). In view of the above-mentioned merits, this N-doped hierarchical porous carbon is anticipated to be a promising material for application in supercapacitors and other fields.