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Degradation of the beta-alumina electrolyte in a zebra cell
Beta-alumina solid electrolytes studied were subjected to charge and discharge cycles in a secondary, high energy density Na/beta-al~mina/NaA1Cl 4/FeC1 2 cell (known as the Zebra cell) at 250 c. These electrolytes were studied by means of optical microscopy, as well as SEM and EDS analyses to establ...
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| Format: | Thesis |
| Language: | English |
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Centre for Materials Engineering
2024
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| _version_ | 1867613288511045632 |
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| access_status_str | Open Access |
| author | Van Heerden, D P |
| author2 | Hutchings, Ron |
| author_browse | Hutchings, Ron Van Heerden, D P |
| author_facet | Hutchings, Ron Van Heerden, D P |
| author_sort | Van Heerden, D P |
| collection | Thesis |
| description | Beta-alumina solid electrolytes studied were subjected to charge and discharge cycles in a secondary, high energy density Na/beta-al~mina/NaA1Cl 4/FeC1 2 cell (known as the Zebra cell) at 250 c. These electrolytes were studied by means of optical microscopy, as well as SEM and EDS analyses to establish possible failure modes. After cycling little discolouration, or impurity pickup was found to have occurred in the electrolyte. The forms of degradation of the beta-alumina electrolyte identified appeared to be a result of inherent flaws in the betaalumina electrolyte tube, problems due to protracted storage of the tubes, or an apparent interfacial film on the cathode/electrolyte interface. A lead wetting agent was used in the cells to enhance the wetting of the beta-alumina electrolyte by the liquid Na. A study of the this coating after cycling of the cell showed that the coating was adherent irrespective of the number of cycles completed. The coating did not appear to influence cracking of the electrolyte during cycling. Cracking of the beta-alumina electrolyte was found to have initiated from the Na/electrolyte interface. No evidence of crack initiation nor internal damage was found on the cathode/electrolyte interfac~. The cracks through the beta-alumina electrolyte wall were found to have sealed by the formation of a plug consisting largely of Na and Cl. on the basis of EDS analyses of the fracture surface of the sealed crack possible sealing mechanisms are proposed. |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/40084 |
| institution | University of Cape Town (South Africa) |
| language | eng |
| last_indexed | 2026-06-10T12:33:45.686Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository |
| publishDate | 2024 |
| publishDateRange | 2024 |
| publishDateSort | 2024 |
| publisher | Centre for Materials Engineering |
| publisherStr | Centre for Materials Engineering |
| record_format | dspace |
| source_str | UCTD — University of Cape Town Open Access Repository |
| spelling | oai:open.uct.ac.za:11427/40084 Degradation of the beta-alumina electrolyte in a zebra cell Van Heerden, D P Hutchings, Ron Ball, Anthony Material Engineering Beta-alumina solid electrolytes studied were subjected to charge and discharge cycles in a secondary, high energy density Na/beta-al~mina/NaA1Cl 4/FeC1 2 cell (known as the Zebra cell) at 250 c. These electrolytes were studied by means of optical microscopy, as well as SEM and EDS analyses to establish possible failure modes. After cycling little discolouration, or impurity pickup was found to have occurred in the electrolyte. The forms of degradation of the beta-alumina electrolyte identified appeared to be a result of inherent flaws in the betaalumina electrolyte tube, problems due to protracted storage of the tubes, or an apparent interfacial film on the cathode/electrolyte interface. A lead wetting agent was used in the cells to enhance the wetting of the beta-alumina electrolyte by the liquid Na. A study of the this coating after cycling of the cell showed that the coating was adherent irrespective of the number of cycles completed. The coating did not appear to influence cracking of the electrolyte during cycling. Cracking of the beta-alumina electrolyte was found to have initiated from the Na/electrolyte interface. No evidence of crack initiation nor internal damage was found on the cathode/electrolyte interfac~. The cracks through the beta-alumina electrolyte wall were found to have sealed by the formation of a plug consisting largely of Na and Cl. on the basis of EDS analyses of the fracture surface of the sealed crack possible sealing mechanisms are proposed. 2024-06-28T13:24:26Z 2024-06-28T13:24:26Z 1988 2024-06-21T18:54:11Z Thesis / Dissertation Masters Master http://hdl.handle.net/11427/40084 eng application/pdf Centre for Materials Engineering Faculty of Engineering and the Built Environment |
| spellingShingle | Material Engineering Van Heerden, D P Degradation of the beta-alumina electrolyte in a zebra cell |
| thesis_degree_str | Master's |
| title | Degradation of the beta-alumina electrolyte in a zebra cell |
| title_full | Degradation of the beta-alumina electrolyte in a zebra cell |
| title_fullStr | Degradation of the beta-alumina electrolyte in a zebra cell |
| title_full_unstemmed | Degradation of the beta-alumina electrolyte in a zebra cell |
| title_short | Degradation of the beta-alumina electrolyte in a zebra cell |
| title_sort | degradation of the beta alumina electrolyte in a zebra cell |
| topic | Material Engineering |
| url | http://hdl.handle.net/11427/40084 |
| work_keys_str_mv | AT vanheerdendp degradationofthebetaaluminaelectrolyteinazebracell |