Sulphur-functionalized graphene towards high performance supercapacitor. (March 2015)

• Record Type: Journal Article
• Authors: Lee, Wee Siang Vincent; Leng, Mei; Li, Meng; Huang, Xiao Lei; Xue, Jun Min
• Is Part Of: Nano energy. Volume 12(2015:Mar.)
• Page Start: 250
• Page End: 257
• Publication Date: 2015-03
• Subjects: Supercapacitors -- Redox reaction -- Thiocarboxylic acid ester -- Sulphone -- Thiourea; Nanoscience -- Periodicals; Nanotechnology -- Periodicals; Nanostructured materials -- Periodicals; Power resources -- Technological innovations -- Periodicals; Nanoscience; Nanostructured materials; Nanotechnology; Power resources -- Technological innovations; Periodicals; 621.042
• DOI: 10.1016/j.nanoen.2014.12.030
• Languages: English
• ISSNs: 2211-2855

Abstract

Abstract: To enhance the energy densities, pseudocapacitive materials are usually added to electric double layer carbonaceous materials. However in the process of energy densities enhancement, power densities are usually lowered which creates a dilemma situation for researchers. Thus to obtain high energy and power densities, a new pseudocapacitive mechanism, to the best of our knowledge, is introduced in this paper. High supercapacitive performance can be obtained by the redox mechanism of thiocarboxylic acid ester to sulphone with the aid of external current. The specific capacitance of the material is enhanced to as high as 1089 F g −1 at 1 A g −1, and even at high current density of 50 A g −1, it is able to discharge a respectable 833 F g −1 . The material is able to exhibit high energy density of 43 Wh kg −1 at high power density of 38 kW kg −1 which validates the possibility of a harmonious coexistence between high energy density and high power density. Graphical abstract: Sulphur functionalized graphene aerogel was prepared such that sulphur functional group in the form of thiocarboxylic acid ester was chemically grafted onto the graphene oxide sheet. The material was able to exhibit high energy density of 43 Wh kg −1 at high power density of 38, 000 W kg −1 which validates the possibility of a harmonious coexistence between high energy density and high power density. Highlights: Pesudocapacitive reaction of thiocarboxylic acid ester to sulphone is proposed which contributes to significant pseudocapacitance. XPS study proved the sulphur functional group conversion during charge/discharge process. Sulphurization of graphene oxide sheet using thiourea via a simple self-assembly process. Superior electrochemical performance displayed in sulphur functionalized graphene is noteworthy in supercapacitor research.