Atomistic simulations of interfacial defect structures of nanoscale solid oxide electrolytes
Abstract/Contents
- Abstract
- A Hybrid Monte Carlo - Molecular Dynamics algorithm was developed to sample the equilibrium distributions of point defects near the (100) surface and two types of pure tilt grain boundaries ([sigma]5(310)/[001] and [sigma]13(510)/[001]) in nanoscale yttria-stabilized zirconia and gadolinia-doped ceria. The simulations predict the first large-scale equilibrium distributions of dopant cations and oxygen vacancies near the three types of interfaces where both kinds display considerable amounts of segregation. The results are compared with various experimental observations, which are qualitatively consistent with the theoretical predictions. The simulation results offer new findings that were not accessible by experiments such as elemental distributions on the atomic scale, the effects of pressure and doping level on dopant segregation, and the effect of defect segregation on the ionic diffusivity. The simulations also reveal the strong dependence of defect segregation on the microscopic structure of the interface. Dopant segregation is triggered by the high concentration of oxygen vacancies at the interface due to lower formation energies and elastic strain due to size misfit between host and dopant cations, but the final distribution profiles are largely determined by the interactions between point defects. The newly proposed segregation mechanism sheds light on the understanding of equilibrium defect structures in these ionic oxides.
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 | Lee, Hark Bum |
|---|---|
| Associated with | Stanford University, Department of Mechanical Engineering. |
| Primary advisor | Cai, Wei |
| Primary advisor | Prinz, F. B |
| Thesis advisor | Cai, Wei |
| Thesis advisor | Prinz, F. B |
| Thesis advisor | Reed, Evan J |
| Primaryadvisor | Reed, Evan J |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Hark B. Lee. |
|---|---|
| Note | Submitted to the Department of Mechanical Engineering. |
| Thesis | Ph.D. Stanford University 2012 |
| Location | electronic resource |
Access conditions
- Copyright
- © 2012 by Hark Bum Lee
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