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Xu K, Hung SW, Si W, Wu Y, Huo C, Yu P, Zhong X, Zhu J. Topotactically transformable antiphase boundaries with enhanced ionic conductivity. Nat Commun 2023; 14:7382. [PMID: 37968326 PMCID: PMC10651924 DOI: 10.1038/s41467-023-43086-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 10/30/2023] [Indexed: 11/17/2023] Open
Abstract
Engineering lattice defects have emerged as a promising approach to effectively modulate the functionality of devices. Particularly, antiphase boundaries (APBs) as planar defects have been considered major obstacles to optimizing the ionic conductivity of mixed ionic-electronic conductors (MIECs) in solid oxide fuel applications. Here our study identifies topotactically transformable APBs (tt-APBs) at the atomic level and demonstrates that they exhibit higher ionic conductivity at elevated temperatures as compared to perfect domains. In-situ observation at the atomic scale tracks dynamic oxygen migration across these tt-APBs, where the abundant interstitial sites between tetrahedrons facilitate the ionic migration. Furthermore, annealing in an oxidized atmosphere can lead to the formation of interstitial oxygen at these APBs. These pieces of evidence clearly clarify that the tt-APBs can contribute to oxygen conductivity as anion diffusion channels, while the topotactically non-transformable APBs cannot. The topotactic transformability opens the way of defect engineering strategies for improving ionic transportation in MIECs.
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Grants
- X.Y. Z is grateful for the financial supports from National Natural Science Foundation of China (52171014, 52011530124, 52025024), Science, Technology and Innovation Commission of Shenzhen Municipality (SGDX20210823104200001, JCYJ20210324134402007, HZQB-KCZYB-2020031), the Sino-German Mobility Programme by the Sino-German Center for Research Promotion (M-0265), Innovation and Technology Fund (ITS/365/21), Science and Technology Department of Sichuan Province (2021YFSY0016), the Research Grants Council of Hong Kong Special Administrative Region, China (Project No. E-CityU101/20, 11302121, 11309822, G-CityU102/20), the European Research Council (Grant No. 856538, project “3D MAGiC”), CityU Strategic Interdisciplinary Research Grant (7020016, 7020043), the City University of Hong Kong (Projects no. 9610484, 9680291, 9678288, 9610607), the City University of Hong Kong Shenzhen Research Institute and City University of Hong Kong Chengdu Research Institute.
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Affiliation(s)
- Kun Xu
- National Center for Electron Microscopy in Beijing, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, PR China.
- Department of Mechanical Engineering, Stanford University, Palo Alto, 94305, USA.
| | - Shih-Wei Hung
- TRACE EM Unit and Department of Materials Science and Engineering, City University of Hong Kong, Kowloon, 999077, Hong Kong SAR, PR China
- City University of Hong Kong Matter Science Research Institute (Futian, Shenzhen), Shenzhen, 518048, PR China
| | - Wenlong Si
- National Center for Electron Microscopy in Beijing, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, PR China
- Ji Hua Laboratory, Foshang, Guangdong, 0757, PR China
| | - Yongshun Wu
- State Key Laboratory of Low Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing, 100084, PR China
| | - Chuanrui Huo
- Beijing Advanced Innovation Center for Materials Genome Engineering, Department of Physical Chemistry, University of Science and Technology Beijing, Beijing, 100083, PR China
| | - Pu Yu
- State Key Laboratory of Low Dimensional Quantum Physics and Department of Physics, Tsinghua University, Beijing, 100084, PR China
| | - Xiaoyan Zhong
- TRACE EM Unit and Department of Materials Science and Engineering, City University of Hong Kong, Kowloon, 999077, Hong Kong SAR, PR China.
- City University of Hong Kong Matter Science Research Institute (Futian, Shenzhen), Shenzhen, 518048, PR China.
- Nanomanufacturing Laboratory (NML), Shenzhen Research Institute, City University of Hong Kong, Shenzhen, 518057, PR China.
- Chengdu Research Institute, City University of Hong Kong, Chengdu, 610200, PR China.
| | - Jing Zhu
- National Center for Electron Microscopy in Beijing, School of Materials Science and Engineering, Tsinghua University, Beijing, 100084, PR China.
- Ji Hua Laboratory, Foshang, Guangdong, 0757, PR China.
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Batuk M, Turner S, Abakumov AM, Batuk D, Hadermann J, Van Tendeloo G. Atomic structure of defects in anion-deficient perovskite-based ferrites with a crystallographic shear structure. Inorg Chem 2014; 53:2171-80. [PMID: 24479580 DOI: 10.1021/ic4028404] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Crystallographic shear (CS) planes provide a new structure-generation mechanism in the anion-deficient perovskites containing lone-pair cations. Pb2Sr2Bi2Fe6O16, a new n = 6 representative of the A(n)B(n)O(3n-2) homologous series of the perovskite-based ferrites with the CS structure, has been synthesized using the solid-state technique. The structure is built of perovskite blocks with a thickness of four FeO6 octahedra spaced by double columns of FeO5 edge-sharing distorted tetragonal pyramids, forming 1/2[110](101)p CS planes (space group Pnma, a = 5.6690(2) Å, b = 3.9108(1) Å, c = 32.643(1) Å). Pb2Sr2Bi2Fe6O16 features a wealth of microstructural phenomena caused by the flexibility of the CS planes due to the variable ratio and length of the constituting fragments with {101}p and {001}p orientation. This leads to the formation of "waves", "hairpins", "Γ-shaped" defects, and inclusions of the hitherto unknown layered anion-deficient perovskites Bi2(Sr,Pb)Fe3O8.5 and Bi3(Sr,Pb)Fe4O11.5. Using a combination of diffraction, imaging, and spectroscopic transmission electron microscopy techniques this complex microstructure was fully characterized, including direct determination of positions, chemical composition, and coordination number of individual atomic species. The complex defect structure makes these perovskites particularly similar to the CS structures in ReO3-type oxides. The flexibility of the CS planes appears to be a specific feature of the Sr-based system, related to the geometric match between the SrO perovskite layers and the {100}p segments of the CS planes.
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Affiliation(s)
- Maria Batuk
- Electron Microscopy for Materials Research (EMAT), University of Antwerp , Groenenborgerlaan 171, B-2020 Antwerp, Belgium
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