Facile preparation of nitrogen-doped porous carbon for high performance symmetric supercapacitor

In this work, the micromolecule l-glutamic acid (Glu) is employed as nitrogen-rich precursor to prepare a novel porous carbon, and ZnCl2 is used as activating agent to improve the surface area and electrochemical performance of the carbon. The nitrogen content of the carbon (Glu-2.5) prepared by Glu and ZnCl2 with a mass ratio of 1:2.5 retains as high as 7.1 % at an activation temperature of 700 °C. The surface area and pore volume of Glu-2.5 are 1007.4 m2 g−1 and 0.57 cm3 g−1, respectively. Glu-2.5 exhibits a high specific capacitance of 330.6 F g−1 in 2 M KOH electrolyte at the current density of 1 A g−1and good cycling stability (89 % retention of capacitance after 5000 charge/discharge cycles). More importantly, the assembled symmetric supercapacitor using Glu-2.5 as electrodes reveals a high energy density (16.7 Wh kg−1) under the power density of 404.7 W kg−1. Owing to its inherent advantages, Glu-2.5 could be a promising and scalable alternative applied to energy storage/conversion.