Supramolecular-driven fabrication of porous nitrogen/sulfur co-doped graphene toward high-performance supercapacitor

Summary Practical applications of graphene-based materials are still inhibited by the serious restacking of graphene nanosheets and single electrical double-layer capacitor energy storage mechanism. To address these issues, nitrogen/sulfur-co-doped reduced graphene oxide (N/S-rGO) was ingeniously prepared by supermolecular-driven in-situ co-dope method. In this article, the GO/L-cysteine supermolecular system was assembled first, the hydrogen bond between L-cysteine and GO is confirmed by the Fourier-transform infrared spectroscopy (FTIR). The theoretical calculation result indicating that L-cysteine is uniformly assembled on GO surface by supermolecular interaction force (dispersion force and hydrogen bond). Due to the oriented supermolecular force, the thus-fabricated N/S-rGO affords customized three-dimensional (3D) porous structure, uniform N,S co-doping, effective electrolyte ion-transport pathways, and satisfactory structural stability. Attributing to the inherent plentiful 3D cavity structure and synergistic effect between N, S heteroatoms, N/S-rGO shows outstanding electrochemical performance, the best-performed N/S-rGO2 possess delightful capacitance (416 F g −1 ), after 20 000 cycles the capacitance retention of N/S-rGO is 110% of the initial value, shows excellent cycle reliability. The N,S-rGO all-solid flexible symmetrical supercapacitor can light up luminous diode for 30 seconds when fully charged, indicating that it provides the possibility of practical application.