Na2Fe2F7: a fluoride-based cathode for high power and long life Na-ion batteries
Despite the high energy density of layered-type cathode materials for Na-ion batteries, their two-dimensional crystal structure suffers a large volume change and phase transition during Na+ de/intercalation, which often results in their poor cycling performances. Thus, a robust three-dimensional fra...
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Veröffentlicht in: | Energy & environmental science 2021-03, Vol.14 (3), p.1469-1479 |
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Hauptverfasser: | , , , , , , , , , , |
Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | Despite the high energy density of layered-type cathode materials for Na-ion batteries, their two-dimensional crystal structure suffers a large volume change and phase transition during Na+ de/intercalation, which often results in their poor cycling performances. Thus, a robust three-dimensional framework with minimal structural change is required for stable electrochemical sodium storage. Here, we introduce an earth-abundant element-based trigonal-type Na–Fe–F compound (Na2Fe2F7) with three-dimensionally interconnected FeF6 octahedra and three-dimensional Na+ diffusion pathways. Through combined studies using first-principles calculations and experiments, we confirm that Na2Fe2F7 delivers excellent power-capability due to large three-dimensional Na+ diffusion pathways as well as ultra-long cycling performance due to negligible structural change during Na+ de/intercalation. These results will guide new insights for material discovery for high performance rechargeable batteries. |
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ISSN: | 1754-5692 1754-5706 |
DOI: | 10.1039/d0ee02803g |