Self‐Generated Template Assisted Construction of Nitrogen Self‐Doped Porous Carbon Nanoframework with Rich Planar Holes for High Energy Density Supercapacitor

Abstract Nitrogen‐doped porous carbon materials with planar holes not only inherit the structure advantages of porous carbon materials, but also have a unique planar porosity and heteroatomic doping feature, showing enormous interest in the field of energy storage and conversion. Nevertheless, rational and controllable design of honeycomb‐like porous carbon materials with rich planar holes remains a tremendous challenge. Herein, we develop a “bottom‐up” self‐assembly of carbon‐ and nitrogen‐rich conjugated polymer and subsequent potassium ferrate (K 2 FeO 4 ) facilitated activation, catalysis and self‐generated template assisted carbonization strategy to construct nitrogen self‐doped honeycomb‐like porous carbon nanoframework (NHPC) with rich planar holes. By exploiting the advantages of the integral and interconnected honeycomb‐like carbon skeleton and rich planar holes (rapid ion/electron diffusion) and the efficient nitrogen doping (improved wettability), the NHPC possesses high specific capacitance of 288 F g −1 at 0.5 A g −1 and outstanding rate performance. In addition, an aqueous symmetric supercapacitor fabricated from NHPC electrodes possesses widened potential window of 2.0 V, high energy density of 23.6 Wh kg −1 at 500 W kg −1 , as well as excellent electrochemical stability (91.2 % capacitance retention after 20,000 cycles).