Careful Choices in Low Temperature Ceramic Processing and Slow Hydration Kinetics Can Affect Proton Conduction in Ceria

Low-temperature ceramic proton conductors such as ceria are important for applications ranging from sensors and resistive switches to new devices like implantable solid-oxide glucose fuel cells. Spray pyrolysis offers a promising fabrication route for proton-conducting ceria, with direct liquid-to-s...

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Main Authors: Simons, Philipp, Torres, Kierstin P., Rupp, Jennifer L. M.
Other Authors: Massachusetts Institute of Technology. Department of Materials Science and Engineering
Format: Article
Language:English
Published: Wiley 2022
Online Access:https://hdl.handle.net/1721.1/140223
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author Simons, Philipp
Torres, Kierstin P.
Rupp, Jennifer L. M.
author2 Massachusetts Institute of Technology. Department of Materials Science and Engineering
author_facet Massachusetts Institute of Technology. Department of Materials Science and Engineering
Simons, Philipp
Torres, Kierstin P.
Rupp, Jennifer L. M.
author_sort Simons, Philipp
collection MIT
description Low-temperature ceramic proton conductors such as ceria are important for applications ranging from sensors and resistive switches to new devices like implantable solid-oxide glucose fuel cells. Spray pyrolysis offers a promising fabrication route for proton-conducting ceria, with direct liquid-to-solid synthesis and control over crystallinity and grain size. To date, there are conflicting reports on ceria's proton conduction mechanism, particularly whether the interior contributes to proton conduction or transport occurs exclusively along a surface water layer. In this work, proton conductivity is observed in sprayed ceria thin films at 125 °C and below. Post-annealed films exhibit higher conductivity than as-deposited films of 3.3 × 10−5 S cm−1 at 25 °C, which is comparable to previous reports and ascribed to the increase in crystallinity and grain size by post-annealing. This indicates that the interior of ceria in fact contributes to proton conduction. Remarkably slow hydration kinetics of ceria are observed, with time-dependent conductivity equilibrating to 9.53 × 10−6 S cm−1 after up to 76 h. This implies kinetics may have suppressed proton conduction in previous studies, explaining the strong fluctuations in reports to date. Slow protonation kinetics must be considered when designing functional ceria ceramics, for example, in electrochemical bio-energy conversion, sensing or neuromorphic computing.
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spelling mit-1721.1/1402232024-05-21T20:11:57Z Careful Choices in Low Temperature Ceramic Processing and Slow Hydration Kinetics Can Affect Proton Conduction in Ceria Simons, Philipp Torres, Kierstin P. Rupp, Jennifer L. M. Massachusetts Institute of Technology. Department of Materials Science and Engineering Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science Low-temperature ceramic proton conductors such as ceria are important for applications ranging from sensors and resistive switches to new devices like implantable solid-oxide glucose fuel cells. Spray pyrolysis offers a promising fabrication route for proton-conducting ceria, with direct liquid-to-solid synthesis and control over crystallinity and grain size. To date, there are conflicting reports on ceria's proton conduction mechanism, particularly whether the interior contributes to proton conduction or transport occurs exclusively along a surface water layer. In this work, proton conductivity is observed in sprayed ceria thin films at 125 °C and below. Post-annealed films exhibit higher conductivity than as-deposited films of 3.3 × 10−5 S cm−1 at 25 °C, which is comparable to previous reports and ascribed to the increase in crystallinity and grain size by post-annealing. This indicates that the interior of ceria in fact contributes to proton conduction. Remarkably slow hydration kinetics of ceria are observed, with time-dependent conductivity equilibrating to 9.53 × 10−6 S cm−1 after up to 76 h. This implies kinetics may have suppressed proton conduction in previous studies, explaining the strong fluctuations in reports to date. Slow protonation kinetics must be considered when designing functional ceria ceramics, for example, in electrochemical bio-energy conversion, sensing or neuromorphic computing. 2022-02-08T16:31:35Z 2022-02-08T16:31:35Z 2021-05-27 2021-02-08 Article http://purl.org/eprint/type/JournalArticle 1616-301X 1616-3028 https://hdl.handle.net/1721.1/140223 Simons, P., Torres, K. P., Rupp, J. L. M., Careful Choices in Low Temperature Ceramic Processing and Slow Hydration Kinetics Can Affect Proton Conduction in Ceria. Adv. Funct. Mater. 2021, 31, 2009630. en http://dx.doi.org/10.1002/adfm.202009630 Advanced Functional Materials Creative Commons Attribution-Noncommercial-Share Alike http://creativecommons.org/licenses/by-nc-sa/4.0/ application/pdf Wiley Wiley
spellingShingle Simons, Philipp
Torres, Kierstin P.
Rupp, Jennifer L. M.
Careful Choices in Low Temperature Ceramic Processing and Slow Hydration Kinetics Can Affect Proton Conduction in Ceria
title Careful Choices in Low Temperature Ceramic Processing and Slow Hydration Kinetics Can Affect Proton Conduction in Ceria
title_full Careful Choices in Low Temperature Ceramic Processing and Slow Hydration Kinetics Can Affect Proton Conduction in Ceria
title_fullStr Careful Choices in Low Temperature Ceramic Processing and Slow Hydration Kinetics Can Affect Proton Conduction in Ceria
title_full_unstemmed Careful Choices in Low Temperature Ceramic Processing and Slow Hydration Kinetics Can Affect Proton Conduction in Ceria
title_short Careful Choices in Low Temperature Ceramic Processing and Slow Hydration Kinetics Can Affect Proton Conduction in Ceria
title_sort careful choices in low temperature ceramic processing and slow hydration kinetics can affect proton conduction in ceria
url https://hdl.handle.net/1721.1/140223
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