N, S co-doped porous carbons from natural Juncus effuses for high performance supercapacitors

In this work, it was presented to prepare N, S co-doped porous carbons derived from Juncus effuses (NSPC) by carbonization, KOH activation, and heteroatoms doping using thiourea as dopant. Microstructures and physicochemical properties of the obtained carbon samples were characterized by using scanning electron microscopy (SEM), transmission electron microscopy (TEM), adsorption/desorption of nitrogen (BET), X-ray diffraction (XRD), Raman spectroscopy (Raman), X-ray photoelectron spectroscopy (XPS) and electrochemical workstation. The NSPC showed outstanding electrochemical performance because of hierarchical porous structures and N, S co-doping. The specific capacitance of the NSPC was 233 F/g at 0.5 A/g, and the capacitance retention reaches 82% for the current density up to 10 A/g, showing a good rate capability. Moreover, symmetric supercapacitor assembled from NSPC revealed high energy density of 15.97 Wh/kg at 500 W/kg. The capacitance of the NSPC still kept about 97% after 5000 cycles at 1.0 A/g. These results confirm that the NSPC is a potential material for high performance supercapacitors.