Facile synthesis of porous carbon materials with extra high nitrogen content for supercapacitor electrodes

Abstract

Herein, we report the facile synthesis of three-dimensional porous nitrogen-doped carbon materials (PNCs) with extra high nitrogen content by means of directly carbonizing nitrogen-enriched precursors, 1,2,4-benzenetriamine dihydrochloride (BTD) and 1,2,4,5-tetraaminobenzene (TAB) with the aid of FeCl₃·6H₂O. The influence of the carbonization temperature and selection of precursors on the morphologies and properties of PNCs were studied using scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET), X-ray diffraction (XRD), etc. Their electrochemical performance was characterized using galavanostatic charge–discharge (GCD), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). A PNC obtained by carbonizing BTD at 450 °C exhibits a high nitrogen content (about 23.85 wt%), and large surface area (1335 m² g⁻¹). As a result, it shows a high specific capacitance of 482 F g⁻¹ at a current density of 1 A g⁻¹ in 1 M H₂SO₄ and excellent cycle stability, 98% retention after 12 000 cycles. Furthermore, a liquid sandwich-structured symmetric supercapacitor assembled from this PNC can power a light stopwatch for about 10 minutes, demonstrating that it is a promising material for supercapacitor electrodes.