2021年2月11日
4.7 V Operation of the Cr4+/Cr3+ Redox Couple in Na3Cr2(PO4)2F3
Chemistry of Materials
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- ,
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- 巻
- 33
- 号
- 4
- 開始ページ
- 1373
- 終了ページ
- 1379
- 記述言語
- 英語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.1021/acs.chemmater.0c04444
- 出版者・発行元
- American Chemical Society (ACS)
Increasing the energy density of sodium-ion battery systems requires highvoltage cathode materials to compensate for the inherently higher redox potential of the Na/Na+ couple compared to the Li/Li+ couple (difference of 0.3 V). Distinct from the high-voltage (>4.2 V) operation using late transition metals (Co-3+Co-/(2+) or Ni3+/Ni2+) in previously reported polyanionic compounds, here we identify the record-high Cr4+/Cr3+ (3d(2)/3d(3)) redox potential in Na3-xCr2(PO4)(2)F-3 (0 < x < 1) at 4.7 V vs Na/Na+. Despite higher d-band position at early 3d transition metal with smaller effective nuclear charge compared to late transition metals, Cr 3d(t(2g)) in less than half-filled state possesses no energy level increments arising from crystal field splitting and intra-orbital Coulombic penalty, leading to extremely high voltages of the Cr4+/Cr3+ (3d(2)/3d(3)) redox couple.
- リンク情報
- ID情報
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- DOI : 10.1021/acs.chemmater.0c04444
- ISSN : 0897-4756
- eISSN : 1520-5002
- Web of Science ID : WOS:000623043600029