Comparison of the in- and across-plane ionic conductivity of highly oriented neodymium doped ceria thin films. (1st April 2018)

• Record Type: Journal Article
• Authors: Baure, George; Zhou, Hanhan; Chung, Ching-Chang; Buck, Marissa N.; Stozhkova, Mariia A.; Jones, Jacob L.; Nino, Juan C.
• Is Part Of: Acta materialia. Volume 147(2018)
• Page Start: 10
• Page End: 15
• Publication Date: 2018-04-01
• Subjects: Epitaxial growth -- Grain boundaries -- Doped ceria -- Impedance spectroscopy -- Thin films; Materials -- Periodicals; Materials science -- Periodicals; Materials -- Mechanical properties -- Periodicals; Metallurgy -- Periodicals; Chemistry, Inorganic -- Periodicals; 620.112
• DOI: 10.1016/j.actamat.2017.12.057
• Languages: English
• ISSNs: 1359-6454

Abstract

Abstract: To determine the effect of grain boundaries and grain orientation on the electrical properties of solid oxide fuel cell electrolytes, a comparison of the in-plane and across-plane ionic conductivity of both strongly and poorly textured, columnar-grained doped ceria thin films was performed within equivalent temperature ranges (150–300 °C). Additionally, the in-plane conductivity of partially amorphous films, polycrystalline films with randomly oriented grains, and single crystal, epitaxial films with no grain boundaries was determined. Pulsed laser deposition permitted the growth of all these types of films and the ability to grow columnar-grained doped ceria on both conducting and insulating surfaces enabled testing of the films both in-plane and across-plane. Compared to the columnar-grained samples, partially amorphous films exhibited a lower conductivity, while epitaxial doped ceria exhibited an enhancement in conductivity of 2 orders of magnitude. Between 300 and 400 °C, the in-plane conductivity of the strongly textured film was higher than the poorly textured one. The conductivity and activation energy in-plane and across-plane for the strongly textured film was similar (2.75 × 10 −5 S/cm, 0.70 eV vs. 5.50 × 10 −5 S/cm, 0.68 eV at 250 °C). In contrast, for the poorly textured films, the in-plane and across-plane conductivity values differed by almost an order of magnitude (2.86 × 10 −5 S/cm, 0.55 eV vs. 1.99 × 10 −4 S/cm, 0.78 eV at 250 °C) suggesting that the boundaries between oriented grains were less resistive. These results further strengthen the argument that grain orientation affects ionic transport through grain boundaries. Graphical abstract: Image 1