title: Incorporation of manganese dioxide within ultraporous activated graphene for high-performance electrochemical capacitors.
abstract: Manganese dioxide (MnO(2)) particles 2-3 nm in size were deposited onto a porous "activated microwave expanded graphite oxide" (aMEGO) carbon scaffold via a self-controlled redox process. Symmetric electrochemical capacitors were fabricated that yielded a specific capacitance of 256 F/g (volumetric: 640 F/cm(3)) and a capacitance retention of 87.7% after 1000 cycles in 1 M H(2)SO(4); when normalized to MnO(2), the specific capacitance was 850 F/g. Asymmetric electrochemical capacitors were also fabricated with aMEGO/MnO(2) as the positive electrode and aMEGO as the negative electrode and had a power density of 32.3 kW/kg (for an energy density of 20.8 Wh/kg), an energy density of 24.3 Wh/kg (for a power density of 24.5 kW/kg), and a capacitance retention of 80.5% over 5000 cycles.
authors.affiliation: Department of Mechanical Engineering and the Materials Science and Engineering Program, The University of Texas at Austin, One University Station C2200, Austin, Texas 78712, USA.
authors.forename: Xin
authors.initials: X
authors.lastname: Zhao
authors.forename: Lili
authors.initials: L
authors.lastname: Zhang
authors.forename: Shanthi
authors.initials: S
authors.lastname: Murali
authors.forename: Meryl D
authors.initials: MD
authors.lastname: Stoller
authors.forename: Qinghua
authors.initials: Q
authors.lastname: Zhang
authors.forename: Yanwu
authors.initials: Y
authors.lastname: Zhu
authors.forename: Rodney S
authors.initials: RS
authors.lastname: Ruoff
mesh_terms: D025802:Electric Capacitance; D004563:Electrochemistry / Q000295:instrumentation*; D004581:Electronics / Q000295:instrumentation*; D004735:Energy Transfer; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006108:Graphite / Q000737:chemistry*; D017895:Manganese Compounds / Q000737:chemistry*; D008422:Materials Testing; D010087:Oxides / Q000737:chemistry*; D016062:Porosity
chemical_list: D017895:Manganese Compounds; D010087:Oxides; D006108:Graphite; C016552:manganese dioxide