High-yield synthesis of N-rich polymer-derived porous carbon with nanorod-like structure and ultrahigh N-doped content for high-performance supercapacitors

Abstract

Porous carbon with unique nanostructure, high heteroatom doping as well as large specific surface area is regarded as an attractive candidate for supercapacitor applications, yet high-yield and free-template synthesis of such material remains a great challenge. Herein, a facile free-template activation method is adopted to transform a nanorod-like N-rich polymer into a new type of N-doped porous carbon by activation of copper chloride (CuCl2). Utilizing this mild activation agent to fulfill one-step carbonization/activation not only can maintain the natural morphology of the precursor and reduce the release of heteroatoms, but also can achieve high-yield synthesis of N-doped porous carbon with abundant micropores. Moreover, these polymer-derived carbons (C-CuCl2) exhibit an unique nanorod-like morphology with hierarchical porous structures, large surface areas (up to 2167.2 m2 g−1), extraordinarily high N doping level (up to 12.9 wt%), and high carbon yields (up to 60 wt%). Owing to these unique characteristics, the best-performed C-CuCl2-800 exhibits a good electrochemical performacne in supercapacitor applications, delivering a delightful capacitance of 271 F g−1 at 0.5 A g−1 and 97% capacitance retention after 10 000 charge-discharge operations at 5.0 A g−1 in a 6.0 M KOH electrolyte. Moreover, a high energy density of 64.5 Wh kg−1 at 350 W kg−1 is also demonstrated for the ionic-liquid-based supercapacitor. Therefore, the facile activation method offers a promising prospect for the high-yield translation of various polymers into porous carbon nanomaterials with high heteroatom doping and large specific surface area.