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Thermodynamic Analysis and Electrochemical Evaluation of CsHSO_4

Uda, Tetsuya and Boysen, Dane A. and Haile, Sossina M. (2005) Thermodynamic Analysis and Electrochemical Evaluation of CsHSO_4. Solid State Ionics, 176 (1-2). pp. 127-133. ISSN 0167-2738.

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A thermodynamic analysis of CsHSO₄ in oxygen and hydrogen atmospheres has been carried out. In an oxygen atmosphere, the phase relationship for the dehydration of CsHSO₄ as a function of H₂O partial pressure was established. It is concluded that CsHSO₄ is stable in a humidified oxygen atmosphere, pH₂O=0.03 atm, up to 170 °C. However, in hydrogen atmospheres, it was affirmed that CsHSO₄ is reduced to H₂S and Cs₂SO₄. Electromotive force (EMF) measurements in a humidified oxygen concentration cell, pH₂O=0.03 atm confirmed the ionic nature of the charge-carrying species. Upon thermal cycling, the voltage obtained from the high temperature phase (T=149 °C) remained unchanged for over 85 h of measurement. The volume change upon transformation to the superprotonic phase, as directly measured by high temperature X-ray powder diffraction, is +0.54%. These results demonstrate not only the stability of CsHSO₄ in oxygen but also the viability of solid acid-based electrochemical devices that would likely be subjected to thermal cycling during operation.

Item Type:Article
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Haile, Sossina M.0000-0002-5293-6252
Alternate Title:Thermodynamic Analysis and Electrochemical Evaluation of CsHSO4
Additional Information:Copyright © 2004 Elsevier B.V. Received 2 October 2003. Revised 5 April 2004. Accepted 27 April 2004. Available online 22 October 2004. Funding for this work was provided by the Office of Naval Research, Office of Electrochemical Power Science and Technology.
Funding AgencyGrant Number
Office of Naval Research (ONR)UNSPECIFIED
Subject Keywords:Fuel cell; Superprotonic transition; Thermodynamics; Solid acid; Proton conductor
Issue or Number:1-2
Classification Code:PACS: 84.60.Dn(Electrochemical conversion and storage: electrochemical cells and batteries; fuel cells); 66.10.Ed(Ionic conduction); 82.60.Hc(Chemical equilibria and equilibrium constants)
Record Number:CaltechAUTHORS:20131122-145418331
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Official Citation:Tetsuya Uda, Dane A. Boysen, Sossina M. Haile, Thermodynamic, thermomechanical, and electrochemical evaluation of CsHSO4, Solid State Ionics, Volume 176, Issues 1–2, 14 January 2005, Pages 127-133, ISSN 0167-2738, (
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:42665
Deposited By: Jonathan Gross
Deposited On:27 Nov 2013 21:48
Last Modified:03 Oct 2019 06:00

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