A Computational Study of Yttria-Stabilized Zirconia: II. Cation Diffusion
© 2017 Acta Materialia Inc. Cubic yttria-stabilized zirconia is widely used in industrial electrochemical devices. While its fast oxygen ion diffusion is well understood, why cation diffusion is much slower—its activation energy (∼5 eV) is 10 times that of anion diffusion—remains a mystery. Indeed,...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Elsevier BV
2021
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| Online Access: | https://hdl.handle.net/1721.1/138010 |
| _version_ | 1826215245863976960 |
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| author | Dong, Yanhao Qi, Liang Li, Ju Chen, I-Wei |
| author2 | Massachusetts Institute of Technology. Department of Nuclear Science and Engineering |
| author_facet | Massachusetts Institute of Technology. Department of Nuclear Science and Engineering Dong, Yanhao Qi, Liang Li, Ju Chen, I-Wei |
| author_sort | Dong, Yanhao |
| collection | MIT |
| description | © 2017 Acta Materialia Inc. Cubic yttria-stabilized zirconia is widely used in industrial electrochemical devices. While its fast oxygen ion diffusion is well understood, why cation diffusion is much slower—its activation energy (∼5 eV) is 10 times that of anion diffusion—remains a mystery. Indeed, all previous computational studies predicted more than 5 eV is needed for forming a cation defect, and another 5 eV for moving one. In contrast, our ab initio calculations have correctly predicted the experimentally observed cation diffusivity. We found Schottky pairs are the dominant defects that provide cation vacancies, and their local environments and migrating path are dictated by packing preferences. As a cation exchanges position with a neighboring vacancy, it passes by an empty interstitial site and severely displaces two oxygen neighbors with shortened Zr-O distances. This causes a short-range repulsion against the migrating cation and a long-range disturbance of the surrounding, which explains why cation diffusion is relatively difficult. In comparison, cubic zirconia's migrating oxygen only minimally disturbs neighboring Zr, which explains why it is a fast oxygen conductor. |
| first_indexed | 2024-09-23T16:20:05Z |
| format | Article |
| id | mit-1721.1/138010 |
| institution | Massachusetts Institute of Technology |
| language | English |
| last_indexed | 2024-09-23T16:20:05Z |
| publishDate | 2021 |
| publisher | Elsevier BV |
| record_format | dspace |
| spelling | mit-1721.1/1380102022-09-29T19:36:07Z A Computational Study of Yttria-Stabilized Zirconia: II. Cation Diffusion Dong, Yanhao Qi, Liang Li, Ju Chen, I-Wei Massachusetts Institute of Technology. Department of Nuclear Science and Engineering Massachusetts Institute of Technology. Department of Materials Science and Engineering © 2017 Acta Materialia Inc. Cubic yttria-stabilized zirconia is widely used in industrial electrochemical devices. While its fast oxygen ion diffusion is well understood, why cation diffusion is much slower—its activation energy (∼5 eV) is 10 times that of anion diffusion—remains a mystery. Indeed, all previous computational studies predicted more than 5 eV is needed for forming a cation defect, and another 5 eV for moving one. In contrast, our ab initio calculations have correctly predicted the experimentally observed cation diffusivity. We found Schottky pairs are the dominant defects that provide cation vacancies, and their local environments and migrating path are dictated by packing preferences. As a cation exchanges position with a neighboring vacancy, it passes by an empty interstitial site and severely displaces two oxygen neighbors with shortened Zr-O distances. This causes a short-range repulsion against the migrating cation and a long-range disturbance of the surrounding, which explains why cation diffusion is relatively difficult. In comparison, cubic zirconia's migrating oxygen only minimally disturbs neighboring Zr, which explains why it is a fast oxygen conductor. 2021-11-09T18:15:25Z 2021-11-09T18:15:25Z 2017-03 2019-09-23T11:33:42Z Article http://purl.org/eprint/type/JournalArticle 1359-6454 https://hdl.handle.net/1721.1/138010 Dong, Yanhao, Qi, Liang, Li, Ju and Chen, I-Wei. 2017. "A Computational Study of Yttria-Stabilized Zirconia: II. Cation Diffusion." Acta Materialia, 126. en 10.1016/j.actamat.2017.01.008 Acta Materialia Creative Commons Attribution-NonCommercial-NoDerivs License http://creativecommons.org/licenses/by-nc-nd/4.0/ application/pdf Elsevier BV arXiv |
| spellingShingle | Dong, Yanhao Qi, Liang Li, Ju Chen, I-Wei A Computational Study of Yttria-Stabilized Zirconia: II. Cation Diffusion |
| title | A Computational Study of Yttria-Stabilized Zirconia: II. Cation Diffusion |
| title_full | A Computational Study of Yttria-Stabilized Zirconia: II. Cation Diffusion |
| title_fullStr | A Computational Study of Yttria-Stabilized Zirconia: II. Cation Diffusion |
| title_full_unstemmed | A Computational Study of Yttria-Stabilized Zirconia: II. Cation Diffusion |
| title_short | A Computational Study of Yttria-Stabilized Zirconia: II. Cation Diffusion |
| title_sort | computational study of yttria stabilized zirconia ii cation diffusion |
| url | https://hdl.handle.net/1721.1/138010 |
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