First-principles prediction of high oxygen-ion conductivity in trilanthanide gallates Ln3GaO6

We systematically investigated trilanthanide gallates (Ln3GaO6) with the space group Cmc21 as oxygen-ion conductors using first-principles calculations. Six Ln3GaO6 (Ln = Nd, Gd, Tb, Ho, Dy, or Er) are both energetically and dynamically stable among 15 Ln3GaO6 compounds, which is consistent with pre...

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Main Authors: Joohwi Lee, Nobuko Ohba, Ryoji Asahi
Format: Article
Language:English
Published: Taylor & Francis Group 2019-12-01
Series:Science and Technology of Advanced Materials
Subjects:
Online Access:http://dx.doi.org/10.1080/14686996.2019.1578183
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spelling doaj-334e33f827fc4595815dc6779332a3f22020-11-25T02:43:21ZengTaylor & Francis GroupScience and Technology of Advanced Materials1468-69961878-55142019-12-0120114415910.1080/14686996.2019.15781831578183First-principles prediction of high oxygen-ion conductivity in trilanthanide gallates Ln3GaO6Joohwi Lee0Nobuko Ohba1Ryoji Asahi2Toyota Central R&D Laboratories, IncToyota Central R&D Laboratories, IncToyota Central R&D Laboratories, IncWe systematically investigated trilanthanide gallates (Ln3GaO6) with the space group Cmc21 as oxygen-ion conductors using first-principles calculations. Six Ln3GaO6 (Ln = Nd, Gd, Tb, Ho, Dy, or Er) are both energetically and dynamically stable among 15 Ln3GaO6 compounds, which is consistent with previous experimental studies reporting successful syntheses of single phases. La3GaO6 and Lu3GaO6 may be metastable despite a slightly higher energy than those of competing reference states, as phonon calculations predict them to be dynamically stable. The formation and the migration barrier energies of an oxygen vacancy (VO) suggest that eight Ln3GaO6 (Ln = La, Nd, Gd, Tb, Ho, Dy, Er, or Lu) can act as oxygen-ion conductors based on VO. Ga plays a role of decreasing the distances between the oxygen sites of Ln3GaO6 compared with those of Ln2O3 so that a VO migrates easier with a reduced migration barrier energy. Larger oxygen-ion diffusivities and lower migration barrier energies of VO for the eight Ln3GaO6 are obtained for smaller atomic numbers of Ln having larger radii of Ln3+. Their oxygen-ion conductivities at 1000 K are predicted to have a similar order of magnitude to that of yttria-stabilized zirconia.http://dx.doi.org/10.1080/14686996.2019.1578183oxygen-ion conductorln3gao6lanthanide gallatefirst-principles material design
collection DOAJ
language English
format Article
sources DOAJ
author Joohwi Lee
Nobuko Ohba
Ryoji Asahi
spellingShingle Joohwi Lee
Nobuko Ohba
Ryoji Asahi
First-principles prediction of high oxygen-ion conductivity in trilanthanide gallates Ln3GaO6
Science and Technology of Advanced Materials
oxygen-ion conductor
ln3gao6
lanthanide gallate
first-principles material design
author_facet Joohwi Lee
Nobuko Ohba
Ryoji Asahi
author_sort Joohwi Lee
title First-principles prediction of high oxygen-ion conductivity in trilanthanide gallates Ln3GaO6
title_short First-principles prediction of high oxygen-ion conductivity in trilanthanide gallates Ln3GaO6
title_full First-principles prediction of high oxygen-ion conductivity in trilanthanide gallates Ln3GaO6
title_fullStr First-principles prediction of high oxygen-ion conductivity in trilanthanide gallates Ln3GaO6
title_full_unstemmed First-principles prediction of high oxygen-ion conductivity in trilanthanide gallates Ln3GaO6
title_sort first-principles prediction of high oxygen-ion conductivity in trilanthanide gallates ln3gao6
publisher Taylor & Francis Group
series Science and Technology of Advanced Materials
issn 1468-6996
1878-5514
publishDate 2019-12-01
description We systematically investigated trilanthanide gallates (Ln3GaO6) with the space group Cmc21 as oxygen-ion conductors using first-principles calculations. Six Ln3GaO6 (Ln = Nd, Gd, Tb, Ho, Dy, or Er) are both energetically and dynamically stable among 15 Ln3GaO6 compounds, which is consistent with previous experimental studies reporting successful syntheses of single phases. La3GaO6 and Lu3GaO6 may be metastable despite a slightly higher energy than those of competing reference states, as phonon calculations predict them to be dynamically stable. The formation and the migration barrier energies of an oxygen vacancy (VO) suggest that eight Ln3GaO6 (Ln = La, Nd, Gd, Tb, Ho, Dy, Er, or Lu) can act as oxygen-ion conductors based on VO. Ga plays a role of decreasing the distances between the oxygen sites of Ln3GaO6 compared with those of Ln2O3 so that a VO migrates easier with a reduced migration barrier energy. Larger oxygen-ion diffusivities and lower migration barrier energies of VO for the eight Ln3GaO6 are obtained for smaller atomic numbers of Ln having larger radii of Ln3+. Their oxygen-ion conductivities at 1000 K are predicted to have a similar order of magnitude to that of yttria-stabilized zirconia.
topic oxygen-ion conductor
ln3gao6
lanthanide gallate
first-principles material design
url http://dx.doi.org/10.1080/14686996.2019.1578183
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