Diethanolamine-Assisted Preparation of Reed Flower-Derived Nitrogen-Doped Porous Carbon for Supercapacitor Electrodes

Reed flower (RF)-derived porous carbon-based electrodes are produced with KOH as the activating agent and diethanolamine (DEA) as the additive via a facile method without precarbonization. DEA with good wettability can facilitate the permeation of KOH through plant tissues, thus enhancing the KOH activation and increasing the specific surface area (SSA) as well as the pore volume. In addition, DEA as a nitrogen-doping agent can also increase the nitrogen content of carbon materials. The porous carbon synthesized with DEA (RFAC-N) exhibits a significantly larger SSA of 1691 m² g^–1, an evidently higher pore volume of 1.08 m³ g^–1, and a higher N content (1.93 wt %) than that synthesized without DEA. Examined in a symmetric two-electrode electrochemical test system with KOH as the electrolyte, RFAC-N presents a high specific capacitance (254.3 F g^–1 at a current density of 1 A g^–1), superb rate performance (192.7 F g^–1 at 30 A g^–1), a high energy density of 9.40 Wh kg^–1, good reversibility, and excellent long cycle stability (89.5% capacity retention after 10,000 cycles at 10 A g^–1). Possessing impressive properties and performance, the N-doped biomass-derived porous carbon materials with a high N content, as synthesized with a facile method presented in this work, demonstrate their vast potential in application in high-performance energy storage devices.