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Iridium‐ruthenium‐oxide coatings for supercapacitors
Author(s) -
Ullah Nehar,
McArthur Mark A.,
Omanovic Sasha
Publication year - 2015
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.22318
Subject(s) - ruthenium oxide , materials science , oxide , dielectric spectroscopy , cyclic voltammetry , supercapacitor , electrochemistry , capacitance , bimetallic strip , coating , chemical engineering , scanning electron microscope , ruthenium , electrode , metal , nanotechnology , metallurgy , composite material , chemistry , catalysis , engineering , biochemistry
Electrochemical, topographical, and morphological properties of thermally‐prepared Ir x ‐Ru 1‐x ‐oxide coatings of various compositions (0 < x ≤ 1), formed on a Ti metal substrate, were investigated for their potential application as supercapacitor (SC) electrodes employing scanning electron microscopy and electrochemical techniques of cyclic voltammetry, galvanostatic charge/discharge cycling, and electrochemical impedance spectroscopy. A current state‐of‐the‐art pure ruthenium oxide (RuO 2 ) coating showed relatively low performance compared to other bimetallic Ir x Ru 1‐x ‐oxide coatings operated under the same experimental conditions. An electrochemically‐activated Ir 0.4 Ru 0.6 ‐oxide coating yielded the highest capacitance value (85 mF cm −2 ). Prolonged electrochemical cycling of the Ir/Ru‐oxide coatings in a corrosive phosphate‐buffered saline pH = 7.4, performed within an extreme potential window of 5 V, revealed an excellent stability of the coatings. In addition, this cycling procedure enabled a significant increase in capacitance for all coating compositions. It was shown that the areal capacitance (C GA ) of these coatings is strongly dependent upon the nature of the components of which the metal oxide is composed. The addition of IrO 2 to RuO 2 improved the stability and capacitive performance of the thermally‐prepared Ir‐Ru‐oxide coatings.