Preparation of nitrogen and sulfur co-doped graphene aerogel with hierarchical porous structure using ionic liquid precursor for high-performance supercapacitor
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In this paper, nitrogen and sulfur co-doped graphene aerogel (NS-GA) was successfully prepared using ionic liquid 1-(4-mercaptobutyl)-3-methylimidazolium bromide (HS-BMIMBr) as both reductant and dopant by a one-step hydrothermal method. The results of X-ray diffraction indicate that the doping of heteroatoms into graphene increases its degree of defects. In addition, scanning electron microscopy measurements and nitrogen adsorption–desorption analysis reveal that the as-prepared NS-GA has unique hierarchical porous nanostructures, which supply efficient networks for ionic transports and electron transfer. The symmetric electrical double-layer capacitors (EDLCs) based on the NS-GA with ionic liquid (1-ethyl-3-methylimidazolium tetrafluoroborate, EMIMBF4) as the electrolyte show excellent capacitive performance. And the NS-GA has a high specific capacitance of 182.3 F g−1 at a current density of 1 A g−1. Moreover, there is a high energy density of 101 Wh kg−1 at a power density of 1 kW kg−1. Therefore, the NS-GA can be considered as a favorable electrode material for high-performance energy storage devices.
KeywordsNitrogen and sulfur co-doped Ionic liquid Hierarchical porous structure Supercapacitor
This work was financially supported by the National Natural Science Foundation of China (Nos. 21573058, 21303044, and 21173070) and Program for Innovative Research Team in Science and Technology in University of Henan Province (15IRTSTHN 003, 17IRTSTHN 001).
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