N/S Codoped Three-Dimensional Porous Carbons for High- Performance Supercapacitors with Remarkable Rate Performance

Supercapacitors have been extensively used as commercial energy storage devices. However, to date, it has remained a huge challenge to create efficient supercapacitors due to a poor comprehension of the relationship between the pore structure and electrochemical performances of electrode materials. In this work, the fabrication of N/S codoped three-dimensional porous carbons by a two-step method is reported. First, sulfonated graphene oxide (SGO) is reacted with PVA and melamine formaldehyde (MF) resin to form a precursor with 3D cross-linked network structure, and then the precursors are carbonized and activated with KOH. The optimum porous carbon (ASNPC-1) exhibits a superior specific surface area of 3281 m2 g-1 as well as excellent electrochemical properties. ASNPC-1 offers a prominent specific capacitance of 386.1 F g-1 at the current density of 0.5 A g-1, which displays excellent rate performance with a capacitance retention rate of 61.9% at 50 A g-1 due to the unique porous structure. Furthermore, the assembled symmetric supercapacitor achieves a high energy density of 14.4 Wh kg-1 at a power density of 700 W kg-1 in 6 M KOH. Hence, this work proposes a facile method for developing high-performance supercapacitors, which is expected for applications in the promising field of energy storage.