title: 3D macroporous graphene frameworks for supercapacitors with high energy and power densities.
abstract: In order to develop energy storage devices with high power and energy densities, electrodes should hold well-defined pathways for efficient ionic and electronic transport. Herein, we demonstrate high-performance supercapacitors by building a three-dimensional (3D) macroporous structure that consists of chemically modified graphene (CMG). These 3D macroporous electrodes, namely, embossed-CMG (e-CMG) films, were fabricated by using polystyrene colloidal particles as a sacrificial template. Furthermore, for further capacitance boost, a thin layer of MnO(2) was additionally deposited onto e-CMG. The porous graphene structure with a large surface area facilitates fast ionic transport within the electrode while preserving decent electronic conductivity and thus endows MnO(2)/e-CMG composite electrodes with excellent electrochemical properties such as a specific capacitance of 389 F/g at 1 A/g and 97.7% capacitance retention upon a current increase to 35 A/g. Moreover, when the MnO(2)/e-CMG composite electrode was asymmetrically assembled with an e-CMG electrode, the assembled full cell shows remarkable cell performance: energy density of 44 Wh/kg, power density of 25 kW/kg, and excellent cycle life.
authors.affiliation: Division of Materials Science, Korea Basic Science Institute, Daejeon, 305-333, Republic of Korea.
authors.forename: Bong Gill
authors.initials: BG
authors.lastname: Choi
authors.forename: Minho
authors.initials: M
authors.lastname: Yang
authors.forename: Won Hi
authors.initials: WH
authors.lastname: Hong
authors.forename: Jang Wook
authors.initials: JW
authors.lastname: Choi
authors.forename: Yun Suk
authors.initials: YS
authors.lastname: Huh