Jovaní, M., Beltrán-Mir, H. orcid.org/0000-0002-7836-1602, Cordoncillo, E. et al. (1 more author) (2017) Atmosphere- and Voltage-Dependent Electronic Conductivity of Oxide-Ion-Conducting Zr1-xYxO2-x/2 Ceramics. Inorganic Chemistry, 56 (12). pp. 7081-7088. ISSN 0020-1669
Abstract
Cubic, fluorite-structured solid solutions Zr1-xYxO2-x/2 (YSZ; x = 0.4-0.7) were prepared by sol-gel synthesis. Impedance measurements on pellets of 85% approximate density sintered at 1300 °C for 24 h showed strong evidence of oxide ion conduction with an inclined Warburg spike at low frequencies and capacitance values of ∼10(-6) F cm(-1) at 40 Hz. Arrhenius plots of total pellet conductivities were linear with activation energies of 1.4-1.56 eV. The conductivity decreased with x and was 2-4 orders of magnitude lower than that with optimized YSZ, x = 0.08. When the atmosphere was changed from N2 to O2 during impedance measurements, two reversible effects were seen: the Warburg spike contracted greatly, and the sample resistance decreased. These effects were more noticeable at higher x and are attributed to the introduction of p-type electronic conduction, in parallel with the preexisting oxide ion conduction. A similar reversible result was observed upon application of a direct-current (dc) bias during impedance measurements. When either pO2 is increased or a dc bias is applied, hole creation is believed to arise by the ionization of underbonded oxide ions situated near the Y(3+) dopant ions. The ionized electrons are trapped at surface oxygen species, and the holes that are left on oxygen are responsible for p-type conduction. The electrolytic domain of x = 0.4-0.7 extends up to approximately 10(-2) atm of O2 before p-type conduction is observed. The upper pO2 limit of the electrolytic domain of x = 0.08 is not known but is likely to be close to or slightly above 1 atm of O2.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2017 American Chemical Society. This is an author produced version of a paper subsequently published in Inorganic Chemistry. Uploaded in accordance with the publisher's self-archiving policy. |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Engineering (Sheffield) > Department of Materials Science and Engineering (Sheffield) |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 08 Jun 2017 10:02 |
Last Modified: | 26 May 2018 00:38 |
Published Version: | https://doi.org/10.1021/acs.inorgchem.7b00673 |
Status: | Published |
Publisher: | American Chemical Society |
Refereed: | Yes |
Identification Number: | 10.1021/acs.inorgchem.7b00673 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:117366 |