Electrochemical characterization of single-layer MnO2 nanosheets as a high-capacitance pseudocapacitor electrode

Kazuya Kai; Yoji Kobayashi; Yuki Yamada; Kohei Miyazaki; Takeshi Abe; Yoshiharu Uchimoto; Hiroshi Kageyama

doi:10.1039/C2JM31080E

Electrochemical characterization of single-layer MnO₂nanosheets as a high-capacitance pseudocapacitor electrode

Kazuya Kai,^a Yoji Kobayashi,^a Yuki Yamada,^a Kohei Miyazaki,^a Takeshi Abe,^a Yoshiharu Uchimoto^b and Hiroshi Kageyama*^ac

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* Corresponding authors

^a Department of Energy and Hydrocarbon Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto, Japan
E-mail: kage@scl.kyoto-u.ac.jp
Fax: +81-(0)75-383-2510
Tel: +81-(0)75-383-2506

^b Department of Interdisciplinary Environment, Graduate School of Human and Environmental Studies, Kyoto University, Yoshida-nihonmatsu-cho, Sakyo-ku, Kyoto 606-8501, Japan

^c Institute for Integrated Cell-Materials Science, Kyoto University, Sakyo-ku, Kyoto 606-8501, Japan

Abstract

A MnO₂/carbon composite comprised of single layer MnO₂ nanosheets and acetylene black (AB) was assembled by simply mixing a MnO₂ nanosheet colloidal suspension and AB suspension. MnO₂ nanosheets were synthesized by a one-pot procedure and adsorbed onto AB aggregates as a single layer (monosheets) through electrostatic interactions. The one-pot synthesis ensures no unexfoliated material, unlike previous preparations. Galvanostatic charge–discharge measurements and cyclic voltammetry in organic electrolytes demonstrate that the MnO₂/AB composite exhibits an excellent specific capacity and capacitance of 400 mA h g⁻¹ and 739 F g⁻¹, respectively, at a scan rate of 1 mV s⁻¹. The obtained specific capacity considerably exceeds the theoretical capacity; this can be explained by the extremely high fraction of single layer sheets from the one-pot procedure.

Article information

https://doi.org/10.1039/C2JM31080E

Article type

Paper

Submitted

21 Feb 2012

Accepted

01 Jun 2012

First published

22 Jun 2012

Download Citation

J. Mater. Chem., 2012,22, 14691-14695

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Electrochemical characterization of single-layer MnO₂ nanosheets as a high-capacitance pseudocapacitor electrode

K. Kai, Y. Kobayashi, Y. Yamada, K. Miyazaki, T. Abe, Y. Uchimoto and H. Kageyama, J. Mater. Chem., 2012, 22, 14691 DOI: 10.1039/C2JM31080E

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Journal of Materials Chemistry