A facile synthesis of nitrogen-doped hierarchical porous carbon with hollow sphere structure for high-performance supercapacitors

In this work, nitrogen-doped carbon with hierarchical porous and hollow sphere structure has been synthesized through a simple and facile route of spray drying using glycine as the nitrogen-containing carbon source. After KOH activation, the prepared material (NHPCA) shows a large specific surface area of 962 m2 g−1 with moderate N-doping of 5.74% and exhibits a high specific capacitance of 271 F g−1 in 6 M KOH electrolyte at 1.0 A g−1, remarkable rate capability and particularly stable cycling performance with no significant specific capacitance drop after 10000 cycles at 1.0 A g−1. The excellent electrochemical properties come from the unique structure and the doping of nitrogen. The hierarchical pore structure improves the efficiency of electrolyte ions transport, and diffusion and the hollow sphere structure further facilitates mass transport. The doping of nitrogen increases the total capacitance by providing redox pseudo-capacitance. The results indicate the as-prepared nitrogen-doped carbon with hierarchical porous and hollow sphere structure can be used as a hopeful candidate for an efficient electrode of commercial supercapacitors devices.