title: Electroactive nanoparticle directed assembly of functionalized graphene nanosheets into hierarchical structures with hybrid compositions for flexible supercapacitors.
abstract: Hierarchical structures of hybrid materials with the controlled compositions have been shown to offer a breakthrough for energy storage and conversion. Here, we report the integrative assembly of chemically modified graphene (CMG) building blocks into hierarchical complex structures with the hybrid composition for high performance flexible pseudocapacitors. The formation mechanism of hierarchical CMG/Nafion/RuO2 (CMGNR) microspheres, which is triggered by the cooperative interplay during the in situ synthesis of RuO2 nanoparticles (NPs), was extensively investigated. In particular, the hierarchical CMGNR microspheres consisting of the aggregates of CMG/Nafion (CMGN) nanosheets and RuO2 NPs provided large surface area and facile ion accessibility to storage sites, while the interconnected nanosheets offered continuous electron pathways and mechanical integrity. The synergistic effect of CMGNR hybrids on the supercapacitor (SC) performance was derived from the hybrid composition of pseudocapacitive RuO2 NPs with the conductive CMGNs as well as from structural features. Consequently, the CMGNR-SCs showed a specific capacitance as high as 160 F g(-1), three-fold higher than that of conventional graphene SCs, and a capacitance retention of >95% of the maximum value even after severe bending and 1000 charge-discharge tests due to the structural and compositional features.
authors.affiliation: Department of Chem. & Biomolecular Eng. (BK 21), Korea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of Korea.
authors.forename: Bong Gill
authors.initials: BG
authors.lastname: Choi
authors.forename: Yun Suk
authors.initials: YS
authors.lastname: Huh
authors.forename: Won Hi
authors.initials: WH
authors.lastname: Hong
authors.forename: David
authors.initials: D
authors.lastname: Erickson
authors.forename: Ho Seok
authors.initials: HS
authors.lastname: Park
mesh_terms: D025802:Electric Capacitance; D005465:Fluorocarbon Polymers / Q000737:chemistry; D006108:Graphite / Q000737:chemistry*; D053758:Nanoparticles / Q000737:chemistry*; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D017975:Ruthenium Compounds / Q000737:chemistry
chemical_list: D005465:Fluorocarbon Polymers; D017975:Ruthenium Compounds; C029017:ruthenium dioxide; C040402:perfluorosulfonic acid; D006108:Graphite