Preparation of N/O co-doped porous carbon by a one-step activation method for supercapacitor electrode materials

Heteroatom-doped carbon materials used in supercapacitors are low in cost and demonstrate extraordinary performance. Here, ethylenediamine tetraacetic acid (EDTA) with intrinsic N and O elements is selected as a raw material for the preparation of heteroatom self-doped porous carbon. Furthermore, N/O self-doped porous carbon with a large surface area has been successfully prepared using K₂CO₃ as the activator. The derived sample with a 1 : 2 molar ratio of EDTA to K₂CO₃ (EK-2) demonstrates a porous structure, rich defects, a large surface area of 2057 m² g^-1 and a micropore volume of 0.25 cm³ g^-1. Benefiting from high N content (2.89 at%) and O content (10.75 at%), EK-2 exhibits superior performance, including high capacitance of 325 F g^-1 at 1 A g^-1 and outstanding cycling stability with 96.8% retention after 8000 cycles at 10 A g^-1, which strongly confirms its immense potential toward many applications. Additionally, the maximum energy density of EK-2 reaches was 17.01 W h kg^-1 at a power density of 350 W kg^-1 in a two-electrode system. This facile and versatile strategy provides a scalable approach for the batch synthesis of N/O co-doped carbonaceous electrode materials for energy storage.