title: Solubility-Dependent NiMoO4Nanoarchitectures: Direct Correlation between Rationally Designed Structure and Electrochemical Pseudokinetics.
abstract: Tailoring the binary metal oxide along with developing new synthetic methods for controlling resultant nanostructures in a predictive way is an essential requirement for achieving the further improved electrochemical performance of pseudocapacitors. Here, through a rational design of the supersaturation-mediated driving force for hydrothermal nucleation and crystal growth, we successfully obtain one-dimensional (1-D) nickel molybdenum oxide (NiMoO4) nanostructures with controlled aspect ratios. The morphology of the 1-D NiMoO4nanostructures can be tuned from a low to a high aspect ratio (over a range of diameter sizes from 80 to 800 nm). Such a controllable structure provides a platform for understanding the electrochemical relationships in terms of fast relaxation times and improved ion-diffusion coefficients. We show that the 1-D NiMoO4electrode with a high aspect ratio (HAR) exhibits a much higher specific capacitance of 1335 F g-1at a current density of 1 A g-1compared to the other electrodes with a relatively low aspect ratio, which is due to the unique physical and chemical structure being suitable for electrochemical kinetics. We further demonstrate that an asymmetric supercapacitor consisting of the tailored HAR-NiMoO4electrode can achieve an energy density of 40.7 Wh kg-1and a power density of 16 kW kg-1.
authors.affiliation: Department of Engineering Science, University of Oxford , Parks Road, Oxford OX1 3PJ, United Kingdom.
authors.forename: John
authors.identifier: http://orcid.org/0000-0002-1513-8622
authors.initials: J
authors.lastname: Hong
authors.affiliation: Department of Engineering Science, University of Oxford , Parks Road, Oxford OX1 3PJ, United Kingdom.
authors.forename: Young-Woo
authors.initials: YW
authors.lastname: Lee
authors.affiliation: Department of Engineering Science, University of Oxford , Parks Road, Oxford OX1 3PJ, United Kingdom.
authors.forename: Bo
authors.initials: B
authors.lastname: Hou
authors.affiliation: Research Institute of Convergence of Basic Science, Novel Functional Materials and Device Laboratory, Department of Physics, Hanyang University , Seoul 133-791, Korea.
authors.forename: Wonbae
authors.initials: W
authors.lastname: Ko
authors.affiliation: Department of Engineering Science, University of Oxford , Parks Road, Oxford OX1 3PJ, United Kingdom.
authors.forename: Juwon
authors.initials: J
authors.lastname: Lee
authors.affiliation: Department of Engineering Science, University of Oxford , Parks Road, Oxford OX1 3PJ, United Kingdom.
authors.forename: Sangyeon
authors.initials: S
authors.lastname: Pak
authors.affiliation: Research Institute of Convergence of Basic Science, Novel Functional Materials and Device Laboratory, Department of Physics, Hanyang University , Seoul 133-791, Korea.
authors.forename: JinPyo
authors.initials: J
authors.lastname: Hong
authors.affiliation: Department of Engineering Science, University of Oxford , Parks Road, Oxford OX1 3PJ, United Kingdom.
authors.forename: Stephen M
authors.initials: SM
authors.lastname: Morris
authors.affiliation: Department of Engineering Science, University of Oxford , Parks Road, Oxford OX1 3PJ, United Kingdom.
authors.forename: SeungNam
authors.initials: S
authors.lastname: Cha
authors.affiliation: Department of Engineering Science, University of Oxford , Parks Road, Oxford OX1 3PJ, United Kingdom.
authors.forename: Jung Inn
authors.identifier: http://orcid.org/0000-0002-3155-4327
authors.initials: JI
authors.lastname: Sohn
authors.affiliation: Electrical Engineering Division, Department of Engineering, University of Cambridge , 9 JJ Thomson Avenue, Cambridge CB3 0FA, United Kingdom.
authors.forename: Jong Min
authors.initials: JM
authors.lastname: Kim
keywords: asymmetric supercapacitor; controlled aspect ratio; electrochemical reaction kinetics; energy storage material; nanowire architecture