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Matsuzaki K, Saito K, Ikeda Y, Nambu Y, Yashima M. High Proton Conduction in the Octahedral Layers of Fully Hydrated Hexagonal Perovskite-Related Oxides. J Am Chem Soc 2024; 146:18544-18555. [PMID: 38917482 PMCID: PMC11240259 DOI: 10.1021/jacs.4c04325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/27/2024]
Abstract
Proton conductors have potential applications such as fuel cells, electrolysis cells, and sensors. These applications require new materials with high proton conductivity and high chemical stability at intermediate temperatures. Herein we report a series of new hexagonal perovskite-related oxides, Ba5R2Al2SnO13 (R = Gd, Dy, Ho, Y, Er, Tm, and Yb). Ba5Er2Al2SnO13 exhibited a high proton conductivity without chemical doping (e.g., 0.01 S cm-1 at 303 °C), which is attributed to its high proton concentration and diffusion coefficient. The high diffusion coefficient of Ba5Er2Al2SnO13 can be attributed to the fast proton migration in the octahedral layers. The high proton concentration is attributed to full hydration in hydrated Ba5Er2Al2SnO13 and the large amount of intrinsic oxygen vacancies in the dry sample, as evidenced by both neutron diffraction and thermogravimetric analysis. Ba5Er2Al2SnO13 was found to exhibit high chemical stability under wet atmospheres of O2, air, H2, and CO2. High proton conductivity and high chemical stability indicate that Ba5Er2Al2SnO13 is a superior proton conductor. Ba5R2Al2SnO13 (R = Gd, Dy, Ho, Y, Tm, and Yb) exhibited high electrical conductivity in wet N2, suggesting that these materials also exhibit high proton conductivity. These findings will open new avenues for proton conductors. The high proton conductivity via full hydration and fast proton migration in octahedral layers in highly oxygen-deficient hexagonal perovskite-related materials would be an effective strategy for developing next-generation proton conductors.
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Affiliation(s)
- Kohei Matsuzaki
- Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1-W4-17, O-okayama, Meguro-ku, Tokyo 152-8551, Japan
| | - Kei Saito
- Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1-W4-17, O-okayama, Meguro-ku, Tokyo 152-8551, Japan
| | - Yoichi Ikeda
- Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Yusuke Nambu
- Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
- Organization for Advanced Studies, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
- FOREST, Japan Science and Technology Agency, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
| | - Masatomo Yashima
- Department of Chemistry, School of Science, Tokyo Institute of Technology, 2-12-1-W4-17, O-okayama, Meguro-ku, Tokyo 152-8551, Japan
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