Biobased Nitrogen- and Oxygen-Codoped Carbon Materials for High-Performance Supercapacitor

Nitrogen and oxygen-codoped carbon materials (NOPC-x and NOPC-bis-CN-x) have been prepared from biobased polybenzoxazines by a soft-template method. Subsequently, their textural properties and surface chemistry are characterized by nitrogen isothermal adsorption, Raman spectroscopy, X-ray diffraction, transmission electron microscope (TEM), and X-ray photoelectron spectroscopy (XPS). Results show that the higher content of the cyano group in benzoxazine monomers endows the carbon materials with higher specific surface area, higher graphitization degree, better pore size distribution, and more electrochemically active N-3 and O-2, as well as O-3. The electrochemical performances of the obtained carbons are evaluated by means of cyclic voltammetry (CV), galvanostatic charge/discharge tests (GCD), and electrochemical impedance spectroscopy (EIS). The results show that the NOPC-bis-CN-x systems possess much better electrochemical properties than those of NOPC-x. Especially for NOPC-bis-CN-3, it displays the highest specific capacitance of 167.3 F g(-1) at 1 A g(-1) and a good retention capability of more than 80% at a current density of 10 A g(-1), as well as higher pseudocapacitance and good cycling stability. The excellent electrochemical performance together with the renewable features and the facile preparation route of NOPC-bis-CN-3 make it a promising biobased candidate for supercapacitor electrodes.