One-Step Synergistic Effect to Produce Two-Dimensional N-Doped Hierarchical Porous Carbon Nanosheets for High-Performance Flexible Supercapacitors

Porous carbon-based supercapacitor has been regarded as a promising candidate for powering wearable electronics. To improve its energy density and mechanical flexibility, great efforts have been made to design ideal porous carbon. However, it is still difficult to synthesize ideal porous carbon with reasonable pore size distribution. Herein, glucose-derived two-dimensional nitrogen-doped hierarchical porous carbon nanosheets (2D-NPC) are synthesized through a one-step pyrolysis-activation process. Melamine and potassium oxalate are used to provide synergistic blowing/activation effect and tailor the physicochemical properties of 2D-NPC for energy-storage applications, including 2D morphology, high specific surface area, well-defined hierarchical pores, and rich N-content (6.1 at. %). Benefiting from these unique features, the 2D-NPC-based electrode exhibits a high specific capacitance of 523 F g–1 in 6 M KOH electrolyte in a three-electrode system. The symmetric supercapacitor exhibits a high energy density of 108 W h kg–1 at 900 W kg–1 in an organic electrolyte. The fabricated flexible supercapacitor manifests an areal energy density of 83 μW h cm–2 at an areal power density of 625 μW cm–2. Our work provides a simple method to tune the physicochemical properties of porous carbon toward high-performance flexible supercapacitors.