One‐Step Pyrolysis to Synthesize Non‐Graphitic Nitrogen‐Doped 2D Ultrathin Carbon Nanosheets and Their Application in Supercapacitors

Non‐graphitic nitrogen plays a significant role in determining the electrochemical performance of carbon materials in the field of energy storage. However, the synthesis of carbon materials with a high level of non‐graphitic nitrogen doping is still a great challenge. In this paper, a facile one‐step pyrolysis approach was developed to synthesize 2D carbon nanosheets with a ultrahigh non‐graphitic nitrogen content. Through an ingenious design, g‐C 3 N 4 and NH 3 , both generated during the pyrolysis process, play major roles in the generation of the non‐graphitic nitrogen‐doped carbon nanosheets. The intermediate g‐C 3 N 4 acts as both a self‐sacrificial template and a nitrogen source, whereas NH 3 offers a nitrogen‐enriched chemical atmosphere. Benefiting from the high pyridinic‐nitrogen content of the maternal g‐C 3 N 4 and the reductive atmosphere of NH 3 , the as‐prepared carbon nanosheets exhibit a strikingly high non‐graphitic nitrogen content (up to 17.36 wt.%); also, thanks to the g‐C 3 N 4 self‐sacrificial template, the as‐synthesized carbon nanosheets are 2D with an ultrathin thickness (3–4 nm) and a porous structure. These novel features make the as‐prepared carbon nanosheets an excellent supercapacitor electrode material in terms of superior specific capacitance (316.8 F g −1 at 1 A g −1 ), excellent cycling stability (without obvious capacitance loss after 10 000 cycles at 10 A g −1 ) and high energy density (up to 10.56 Wh kg −1 at a power density of 500 W kg −1 ). This work provides a new idea to prepare non‐graphitic nitrogen enriched carbon materials.