2023 Fiscal Year Final Research Report
Development of iron-based oxide cathodes using insertion/extraction reactions of excess fluoride-ions
| Project/Area Number |
21H02048
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Review Section |
Basic Section 36020:Energy-related chemistry
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| Research Institution | Nara Women's University (2022-2023)
Kyoto University (2021) |
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Principal Investigator |
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| Project Period (FY) |
2021-04-01 – 2024-03-31
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| Keywords | 全固体フッ化物イオン二次電池 / 正極材料 / アニオンレドックス / 分子形成 |
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| Outline of Final Research Achievements |
In this study, Ca-substituted SrFeO2 (CaxSr1-xFeO2) and Ba-substituted SrFeO2 (BaxSr1-xFeO2) based on SrFeO2 with infinite layer structure were focused on, and evaluated their electrochemical properties and clarified their reaction mechanisms. It was clarified that SrFeO2 has Fe in the early stage of charge compensation and O in the late stage of charge compensation, and that more fluoride ions can be inserted than expected from the crystal structure due to the formation of molecular oxygen when O is responsible for charge compensation. Furthermore, it was found that doping Ca into SrFeO2 increased the capacity up to 580 mAhg-1, while doping Ba into SrFeO2 improved the power density by increasing the interlayer distance within the infinite layer structure.
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| Free Research Field |
固体電気化学
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| Academic Significance and Societal Importance of the Research Achievements |
本研究では、SrFeO2がFeの電荷補償とO2分子の形成を伴うOの電荷補償を利用することで、結晶構造から予想されるよりも多くのフッ化物イオンが挿入可能であり、高い可逆容量を発現することを示した。さらにSrFeO2にCaをドープすると容量は最大で580 mAhg-1まで増加すること、Baをドープするとinfinite layer構造内の層間距離が広がることで出力特性が向上することを示した。これらの成果は高容量、高出力な全固体フッ化物イオン二次電池の正極材料を開発する上で重要な知見であり、学術的・社会的意義は大きい。
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