Improving the cathode/electrolyte interface : from alloying electrodes to refining grain boundaries
Abstract/Contents
- Abstract
- Solid oxide fuel cells (SOFCs) have been demonstrated to have great potential for efficiently converting chemical energy to electrical energy. Recent studies have focused on reducing the operating temperature of SOFCs to below 500°C. At such low temperatures, the cathode/electrolyte interface is one of the bottlenecks for better fuel cell performance. In this work, improving the cathode/electrolyte interface was first attempted by replacing pure platinum electrodes with platinum alloy electrodes. Pure platinum electrodes suffer degradation of microstructure over time at elevated temperatures due to The Ostwald ripening. The results show, that in solid oxide fuel cells employing nanoporous Pt-Ni cathodic catalysts instead of pure Pt, better microstructural stabilities, lower electrode impedances, and higher power densities can be achieved at elevated operating temperatures (350-550°C). Independently, improving the cathode/electrolyte interface was also attempted by improving surface structures of the electrolyte. Grain boundary regions of electrolytes were postulated to enhance the rate of oxide ion incorporations. A continuum model was developed to simulate oxide ion diffusion under the influence of electrical fields in polycrystalline oxides. Based on experimental O-18 tracer diffusion data, the model is consistent with enhanced oxide ion incorporation rates in close proximity of the grain boundaries. The results suggest that employing electrolytes with high densities of surface grain boundaries may enhance the performance of low-temperature SOFCs.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2012 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Tian, Xu |
|---|---|
| Associated with | Stanford University, Department of Applied Physics |
| Primary advisor | Prinz, F. B |
| Primary advisor | Shen, Zhi-Xun |
| Thesis advisor | Prinz, F. B |
| Thesis advisor | Shen, Zhi-Xun |
| Thesis advisor | Cui, Yi, 1976- |
| Advisor | Cui, Yi, 1976- |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Xu Tian. |
|---|---|
| Note | Submitted to the Department of Applied Physics. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2012. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2012 by Xu Tian
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
Also listed in
Loading usage metrics...