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Non-stoichiometry, grain boundary transport and chemical stability of proton conducting perovskites

Haile, S. M. and Staneff, G. and Ryu, K. H. (2001) Non-stoichiometry, grain boundary transport and chemical stability of proton conducting perovskites. Journal of Materials Science, 36 (5). pp. 1149-1160. ISSN 0022-2461. https://resolver.caltech.edu/CaltechAUTHORS:20200221-091845242

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Abstract

The interrelationship between defect chemistry, non-stoichiometry, grain boundary transport and chemical stability of proton conducting perovskites (doped alkaline earth cerates and zirconates) has been investigated. Non-stoichiometry, defined as the deviation of the A : M molar ratio in AMO₃ from 1 : 1, dramatically impacts conductivity, sinterability and chemical stability with respect to reaction with CO₂. In particular, alkaline earth deficiency encourages dopant incorporation onto the A-atom site, rather than the intended M-atom site, reducing the concentration of oxygen vacancies. Transport along grain boundaries is, in general, less favorable than transport through the bulk, and thus only in fine-grained materials does microstructure impact the overall electrical properties. The chemical stability of high conductivity cerates is enhanced by the introduction of Zr. The conductivity of BaCe_(0.9−x) Zr_x M_(0.1)O₃ perovskites monotonically decreases with increasing x (increasing Zr content), with the impact of Zr substitution increasing in the order M = Yb → Gd → Nd. Furthermore, the magnitude of the conductivity follows the same sequence for a given zirconium content. This result is interpreted in terms of dopant ion incorporation onto the divalent ion site.


Item Type:Article
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https://doi.org/10.1023/a:1004877708871DOIArticle
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ORCID:
AuthorORCID
Haile, S. M.0000-0002-5293-6252
Additional Information:© 2001 Kluwer Academic Publishers. Issue Date: March 2001. The authors gratefully acknowledge the support of the Irvine Foundation, Hughes Research Labs and the National Science Foundation via a National Young Investigator award. The authors also thank Dr. M.S. Islam for insightful discussions and Dr. Carol Garland for assistance with transmission electron microscopy.
Funders:
Funding AgencyGrant Number
Irvine FoundationUNSPECIFIED
Hughes Research LaboratoriesUNSPECIFIED
NSFUNSPECIFIED
Subject Keywords:Perovskite; Chemical Stability; Alkaline Earth; Zirconium Content; Defect Chemistry
Issue or Number:5
Record Number:CaltechAUTHORS:20200221-091845242
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20200221-091845242
Official Citation:Haile, S.M., Staneff, G. & Ryu, K.H. Non-stoichiometry, grain boundary transport and chemical stability of proton conducting perovskites. Journal of Materials Science 36, 1149–1160 (2001). https://doi.org/10.1023/A:1004877708871
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:101450
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:21 Feb 2020 18:09
Last Modified:21 Feb 2020 18:09

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