Engineering of the Charged Defects at the Perovskite Oxide Surfaces for Exceptionally Stable Solid Oxide Fuel Cell Electrodes
- Title
- Engineering of the Charged Defects at the Perovskite Oxide Surfaces for Exceptionally Stable Solid Oxide Fuel Cell Electrodes
- Author
- 김경학
- Keywords
- Solid oxide fuel cell; Perovskite oxide; Stability; Cation segregation; Charged defects; Heterointerface; Redistribution; Electron transfer
- Issue Date
- 2020-04
- Publisher
- AMER CHEMICAL SOC
- Citation
- ACS APPLIED MATERIALS & INTERFACES, v. 12, no. 19, page. 21494-21504
- Abstract
- Cation segregation, particularly Sr segregation, toward a perovskite surface has a significant effect on the performance degradation of a solid oxide cell (solid oxide electrolysis/fuel cell). Among the number of key reasons generating the instability of perovskite oxide, surface-accumulated positively charged defects (oxygen vacancy, Vo··) have been considered as the most crucial drivers in strongly attracting negatively charged defects (SrA - site′) toward the surface. Herein, we demonstrate the effects of a heterointerface on the redistribution of both positively and negatively charged defects for a reduction of Vo·· at a perovskite surface. We took Sm0.5Sr0.5CoO3-δ (SSC) as a model perovskite film and coated Gd0.1Ce0.9O2-δ (GDC) additionally onto the SSC film to create a heterointerface (GDC/SSC), resulting in an ∼11-fold reduction in a degradation rate of ∼8% at 650 °C and ∼10-fold higher surface exchange (kq) than a bare SSC film after 150 h at 650 °C. Using X-ray photoelectron spectroscopy and electron energy loss spectroscopy, we revealed a decrease in positively charged defects of Vo·· and transferred electrons in an SSC film at the GDC/SSC heterointerface, resulting in a suppression of negatively charged Sr (SrSm′) segregation. Finally, the energetic behavior, including the charge transfer phenomenon, O p-band center, and oxygen vacancy formation energy calculated using the density functional theory, verified the effects of the heterointerface on the redistribution of the charged defects, resulting in a remarkable impact on the stability of perovskite oxide at elevated temperatures.
- URI
- https://pubs.acs.org/doi/10.1021/acsami.9b21919https://repository.hanyang.ac.kr/handle/20.500.11754/165753
- ISSN
- 1944-8244; 1944-8252
- DOI
- 10.1021/acsami.9b21919
- Appears in Collections:
- COLLEGE OF ENGINEERING[S](공과대학) > CHEMICAL ENGINEERING(화학공학과) > Articles
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