Nitrogen/oxygen co-doped porous carbons derived from a facilely-synthesized Schiff-base polymer for high-performance supercapacitor

We report an effective strategy for the preparation of nitrogen/oxygen co-doped porous carbons (DQPACs) based on a facile, low-cost, high-yield polymerization between 2,5-dihydroxy-1,4-benzoquinone and p-phenylenediamine in acetic acid solvent without any catalyst, and then subjected to carbonization and KOH activation at 600-800 degrees C. The resultant DQPAC-700 exhibits abundant micropores, large specific surface area (1659.97 m(2) g(-1)), and a high level of nitrogen/oxygen doping contents (as high as 4.09 wt.% and 10.84 wt.%, respectively). Therefore, the DQPAC-700 is a promising electrode material for supercapacitors, delivering the maximum specific capacitance of 292 F g(-1) at 0.5 A g(-1) and a good rate capacitance of 167 F g(-1) at 50 A g(-1) in 6 M KOH electrolytes. The optimized supercapacitor displays a high cycling stability (capacitance retention up to 96% after 20,000 cycles at 5 A g(-1)) and a moderate energy density (11.3 Wh kg(-1) at 103 W kg(-1)). When using 1 M Na2SO4 solution as the electrolyte, the energy density can be further improved to 25.6 Wh kg(-1). The results indicate that our polymerization approach is facile and effective, which can be extended to develop other nitrogen-rich polymers for the creation of more porous carbon materials with abundant nitrogen/oxygen species.