title: In-situ growth of MnO2crystals under nanopore-constraint in carbon nanofibers and their electrochemical performance.
abstract: Growing MnO2nanocrystals in the bulk of porous carbon nanofibers is conducted in a KMnO4aqueous solution aimed to enhance the electrochemical performance of MnO2. The rate of redox reaction between KMnO4and carbon was controlled by the concentration of KMnO4in a neutral solution. The MnO2nanoparticles grow along with (211) crystal faces when the redox reaction happens on the surface of fibers under 1D constraint, while the nanoparticles grow along with (200) crystal faces when the redox reaction happens in the bulk of fibers under 3D constraint. The composite, where MnO2nanoparticles are formed in the bulk under a constraint, yields an electrode material for supercapacitors showing good electron transport, rapid ion penetration, fast and reversible Faradaic reaction, and excellent rate performance. The capacitance of the composite electrode could be 1282 F g-1under a current density of 0.2 A g-1in 1 M Na2SO4electrolyte. A symmetric supercapacitor delivers energy density of 36 Wh kg-1with power density of 39 W kg-1, and can maintain 7.5 Wh kg-1at 10.3 kW kg-1. It exhibits an excellent electrochemical cycling stability with 101% initial capacitance and 95% columbic efficiency even after 1000 cycles of charge/discharge.
authors.affiliation: State Key Laboratory of Control and Simulation of Power System and Generation Equipments, Tsinghua University, Beijing 100084, China.
authors.forename: TrungHieu
authors.initials: T
authors.lastname: Le
authors.affiliation: State Key Laboratory of Control and Simulation of Power System and Generation Equipments, Tsinghua University, Beijing 100084, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Control and Simulation of Power System and Generation Equipments, Tsinghua University, Beijing 100084, China.
authors.forename: Liu
authors.initials: L
authors.lastname: Yu
authors.affiliation: Laboratory of Advanced Materials, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084, China.
authors.forename: Zheng-Hong
authors.initials: ZH
authors.lastname: Huang
authors.affiliation: Laboratory of Advanced Materials, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084, China.
authors.forename: Feiyu
authors.initials: F
authors.lastname: Kang