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Home  >  Journal list  >  Journal of the Ceramic Society of Japan  >  Vol.122  No.1426 (June) (2014)  >  pp.426-429

Journal of the Ceramic Society of Japan
<<Previous article Vol.122  No.1426 (June) (2014)   pp.426 - 429 Next article>>

Electrode properties of layered tungsten-based oxides for electrochemical capacitors

Eunbum KIM1), Shinya SUZUKI1), Masaru MIYAYAMA1) 2)
1) Research Center for Advanced Science and Technology, The University of Tokyo 2) CREST, JST

Electrochemical properties of layer-structured H2W2O7 for electrochemical capacitors were investigated in an aqueous electrolyte for the first time. H2W2O7 was synthesized from Bi2W2O9 by proton-exchanges with acid treatment. H2W2O7 exhibited a low redox potential of about −0.3 V in a H2SO4 electrolyte solution. The H2W2O7 electrode showed an oxidation capacity of 56 mAh g−1 at a current density of 300 mA g−1, which is equal to the theoretical capacity assuming that 0.5 electrons react with one tungsten ion. H2W2O7 also retained 88% oxidation capacity at a high current density of 2 A g−1 against that at a low current density of 300 mA g−1. It is assumed that redox reaction rate mainly depends on proton diffusion in H2W2O7. Moreover, this material showed excellent cycle stability over 1000 cycles without capacity loss. It is clarified that a H2W2O7 electrode is a promising electrode for electrochemical capacitors featuring a high rate capability and good cycle life.


Keyword:
Electrochemical capacitors, Tungsten oxide, Layered structure, Aqueous electrolyte, Proton capacitors

Received: December 15, 2013
Accepted: February 06, 2014 , Published online: June 01, 2014
Copyright © 2014 The Ceramic Society of Japan

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