Nitrogen and Sulfur-Codoped Porous Carbon Nanospheres with Hierarchical Micromesoporous Structures and an Ultralarge Pore Volume for High-Performance Supercapacitors.

The carbon nanostructure with heteroatom doping having well-designed porosity and a large pore volume plays a vital role in high-performance supercapacitors. Herein, we synthesize hierarchical nitrogen and sulfur-codoped micromesoporous carbon nanospheres (N,S-HPCNSs) with an ultralarge pore volume of 3.684 cm g. The ultralarge pore volume in the N,S-HPCNSs can achieve fast charge storage and high electrochemical utilization due to the rapid mass transport. As a result, N,S-HPCNSs exhibit specific capacitances of 309.4 F g at 0.5 A g and 232.0 F g at 50 A g in a 1 M HSO electrolyte, suggesting a superior rate property. Moreover, the N,S-HPCNSs exhibit a splendid cycling performance after 10,000 cycles with 98.5% capacitance retention. Furthermore, a symmetric supercapacitor reaches an excellent energy density of 27.8 W h kg under 180.0 W kg in a 1 M NaSO electrolyte. The remarkable electrochemical properties of N,S-HPCNSs are caused by the ultralarge pore volume and hierarchical micromesoporous structures of the carbon NSs, which provide a significant way for designing energy storage systems.