title: Three-Dimensional Expanded Graphene-Metal Oxide Film via Solid-State Microwave Irradiation for Aqueous Asymmetric Supercapacitors.
abstract: Carbon-based electrochemical double-layer capacitors and pseudocapacitors, consisting of a symmetric configuration of electrodes, can deliver much higher power densities than batteries, but they suffer from low energy densities. Herein, we report the development of high energy and power density supercapacitors using an asymmetric configuration of Fe2O3 and MnO2 nanoparticles incorporated into 3D macroporous graphene film electrodes that can be operated in a safe and low-cost aqueous electrolyte. The gap in working potential windows of Fe2O3 and MnO2 enables the stable expansion of the cell voltage up to 1.8 V, which is responsible for the high energy density (41.7 Wh kg(-1)). We employ a household microwave oven to simultaneously create conductivity, porosity, and the deposition of metal oxides on graphene films toward 3D hybrid architectures, which lead to a high power density (13.5 kW kg(-1)). Such high energy and power densities are maintained for over 5000 cycles, even during cycling at a high current density of 16.9 A g(-1).
authors.affiliation: Graduate School of Nanoscience and Technology, Korea Advanced Institute of Science and Technology , Daejeon 305-701, Republic of Korea.|Department of Nano Bio Research, National NanoFab Center (NNFC) , Daejeon 305-806, Republic of Korea.
authors.forename: MinHo
authors.initials: M
authors.lastname: Yang
authors.affiliation: Department of Nano Bio Research, National NanoFab Center (NNFC) , Daejeon 305-806, Republic of Korea.
authors.forename: Kyoung G
authors.initials: KG
authors.lastname: Lee
authors.affiliation: Department of Nano Bio Research, National NanoFab Center (NNFC) , Daejeon 305-806, Republic of Korea.
authors.forename: Seok Jae
authors.initials: SJ
authors.lastname: Lee
authors.affiliation: Graduate School of Nanoscience and Technology, Korea Advanced Institute of Science and Technology , Daejeon 305-701, Republic of Korea.|Department of Chemistry and Biochemistry, University of Maryland , College Park, Maryland 20742, United States.
authors.forename: Sang Bok
authors.initials: SB
authors.lastname: Lee
authors.affiliation: Department of Energy and Materials Engineering, Dongguk University-Seoul , Seoul 100-715, Republic of Korea.
authors.forename: Young-Kyu
authors.initials: YK
authors.lastname: Han
authors.affiliation: Department of Chemical Engineering, Kangwon National University , Samcheok 245-711, Republic of Korea.
authors.forename: Bong Gill
authors.initials: BG
authors.lastname: Choi
keywords: graphene; hybrid film; metal oxide; microwave; supercapacitor