title: Water-soluble graphene grafted by poly(sodium 4-styrenesulfonate) for enhancement of electric capacitance.
abstract: Water-soluble poly(sodium 4-styrenesulfonate) modified graphene (PSSS-GR) was successfully synthesized via covalently grafting poly(sodium 4-styrenesulfonate) (PSSS) on the surfaces of graphene (GR) nanosheets. The structure of PSSS-GR was investigated with Fourier transform infrared, x-ray photoelectron and Raman spectroscopy, thermogravimetric analysis, transmission and scanning electron microscopy and atomic force microscopy. The PSSS chains made the GR nanosheets fully exfoliate into a single-layer structure, and the PSSS layer on GR reached 90 wt%. PSSS chains displayed mutually repulsive effects on promoting GR sheets that were more stable in water. The performances of supercapacitors made of PSSS-GR and unmodified GR electrodes were compared using cyclic voltammetry and galvanostatic charge/discharge techniques. The results showed that PSSS is an effective binder for graphene sheets and can increase the specific capacitance of PSSS-GR based supercapacitors and improve their rate capability. The maximum specific capacitance of the PSSS-GR based supercapacitor was 210 F g(-1) at 5 A g(-1), which was 166% higher than for one made of unmodified graphene electrodes. Electrochemical impedance spectroscopy demonstrated fast ion diffusion in the PSSS-GR electrode structure. PSSS-GR based supercapacitors can fulfil one of the essential requirements for potential electric energy storage applications.
authors.affiliation: School of Materials Science and Engineering, Wuhan Institute of Technology, Wuhan 430073, People's Republic of China.
authors.forename: Fei-Peng
authors.initials: FP
authors.lastname: Du
authors.forename: Jing-Jing
authors.initials: JJ
authors.lastname: Wang
authors.forename: Chak-Yin
authors.initials: CY
authors.lastname: Tang
authors.forename: Chi-Pong
authors.initials: CP
authors.lastname: Tsui
authors.forename: Xing-Ping
authors.initials: XP
authors.lastname: Zhou
authors.forename: Xiao-Lin
authors.initials: XL
authors.lastname: Xie
authors.forename: Yong-Gui
authors.initials: YG
authors.lastname: Liao