title: Role of Graphene Oxide Liquid Crystals in Hydrothermal Reduction and Supercapacitor Performance.
abstract: The formation of liquid crystal (LC) phases in graphene oxide (GO) aqueous solution is utilized to develop high-performance supercapacitors. To investigate the effect of LC formation on the properties of subsequently reduced GO (rGO), we compare films prepared through blade-coating of viscous LC-GO solution and ultrasonic spray-coating of diluted GO aqueous dispersion. After hydrothermal reduction under identical conditions, the films show different morphology, oxygen content, and specific capacitance. Trapped water in the LC GO film plays a role in preventing restacking of sheets and facilitating the removal of oxygenated groups during the reduction process. In device architectures with either liquid or polymer electrolyte, the specific capacitance of the blade-coated film is twice as high as that of the spray-coated one. For a blade-coated film with mass loading of 0.115 mg/cm(2), the specific capacitance reaches 286 F/g in aqueous electrolyte and 263 F/g in gelled electrolyte, respectively. This study suggests a route to pilot-scale production of high-performance graphene supercapacitors through blade-coated LC-GO films.
authors.affiliation: School of Materials Science and Engineering, Beihang University , Beijing 100191, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Wang
authors.affiliation: School of Materials Science and Engineering, Beihang University , Beijing 100191, China.
authors.forename: Jinzhang
authors.initials: J
authors.lastname: Liu
authors.affiliation: School of Materials Science and Engineering, Beihang University , Beijing 100191, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: School of Materials Science and Engineering, Beihang University , Beijing 100191, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.affiliation: Siansonic Technology Co. Ltd. , Beijing 101111, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Xian
authors.affiliation: School of Chemistry, Physics, and Mechanical Engineering, Queensland University of Technology , Brisbane 4001, QLD, Australia.
authors.forename: Mojtaba
authors.initials: M
authors.lastname: Amjadipour
authors.affiliation: School of Chemistry, Physics, and Mechanical Engineering, Queensland University of Technology , Brisbane 4001, QLD, Australia.
authors.forename: Jennifer
authors.initials: J
authors.lastname: MacLeod
authors.affiliation: School of Chemistry, Physics, and Mechanical Engineering, Queensland University of Technology , Brisbane 4001, QLD, Australia.
authors.forename: Nunzio
authors.initials: N
authors.lastname: Motta
keywords: coating; energy storage; graphene; liquid crystal; supercapacitor