N/O Codoped Porous Carbons with Layered Structure for High-Rate Performance Supercapacitors

Abstract

Layer-structured, N/O codoped porous carbon materials that are used for supercapacitor electrodes have gained considerable attention recently due to the positive contribution in pseudocapacitance and pore accessibility. Herein, we report the fabrication of N/O codoped porous carbons by using bis(2-chloroethyl)amine hydrochloride as the C/N sources. After heat-treating the single precursor at 260 °C in an air atmosphere, the resultant layered carbonaceous char is subjected to simultaneous carbonization and KOH activation at 800 °C, giving N/O codoped porous carbon (NOC-800). The NOC-800 sample has a layered structure together with an ultrahigh BET surface area (3066 m2 g–1) and a moderate level of N/O contents (1.48 at. % N and 6.75 at. % O). When the NOC-800 material is utilized as a supercapacitor electrode, it displays both ultrahigh capacitance (391 F g–1 at 1.0 A g–1) and high-rate capability (78% of capacitance retention at 1–100 A g–1) in 6.0 M KOH aqueous electrolyte. In addition, the NOC-800-based supercapacitor also displays high energy density (22.2 Wh kg–1 at 437 W kg–1) as well as high cycling stability (91.7% of capacitance retention after 10 000 cycles) in 1.0 M Na2SO4 aqueous electrolyte.