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

Abstract 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 NH₄Cl 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 m² 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 Na₂SO₄ (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.