Synthesis of N/S co-doped porous carbon microspheres based on amino acid protic salt for supercapacitor

Carbon microspheres with well-developed pore structure are highly desirable to be fabricated for high performance supercapacitors, which were governed by the precursors and the processing method to a great degree. Here we report the fabrication of N/S co-doped carbon microspheres based on asparagine protic salt ([Asn][HSO4]) via hydrothermal method. The results showed that the diameter and pore size of the carbon microspheres can be regulated by adjusting the concentration of sodium dodecyl sulfate (SDS). The carbon microspheres activated by NaHCO3 (Asn-5-NaHCO3) can deliver a high specific capacitance of 148 F g−1 at 1 A g−1 as electrodes in symmetric supercapacitors, yielding an energy density of 5.1 Wh kg−1 and a high power density of 250 W kg−1. It was demonstrated that the voltage output and capacity can be further enhanced by integrating supercapacitors in series/parallel mode.