書誌事項
- 公開日
- 2024-03-01
- 権利情報
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- https://creativecommons.org/licenses/by/4.0
- https://creativecommons.org/licenses/by/4.0
- DOI
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- 10.1038/s41563-024-01833-z
- 公開者
- Springer Science and Business Media LLC
この論文をさがす
説明
<jats:title>Abstract</jats:title><jats:p>Oxygen redox cathodes, such as Li<jats:sub>1.2</jats:sub>Ni<jats:sub>0.13</jats:sub>Co<jats:sub>0.13</jats:sub>Mn<jats:sub>0.54</jats:sub>O<jats:sub>2</jats:sub>, deliver higher energy densities than those based on transition metal redox alone. However, they commonly exhibit voltage fade, a gradually diminishing discharge voltage on extended cycling. Recent research has shown that, on the first charge, oxidation of O<jats:sup>2−</jats:sup> ions forms O<jats:sub>2</jats:sub> molecules trapped in nano-sized voids within the structure, which can be fully reduced to O<jats:sup>2−</jats:sup> on the subsequent discharge. Here we show that the loss of O-redox capacity on cycling and therefore voltage fade arises from a combination of a reduction in the reversibility of the O<jats:sup>2−</jats:sup>/O<jats:sub>2</jats:sub> redox process and O<jats:sub>2</jats:sub> loss. The closed voids that trap O<jats:sub>2</jats:sub> grow on cycling, rendering more of the trapped O<jats:sub>2</jats:sub> electrochemically inactive. The size and density of voids leads to cracking of the particles and open voids at the surfaces, releasing O<jats:sub>2</jats:sub>. Our findings implicate the thermodynamic driving force to form O<jats:sub>2</jats:sub> as the root cause of transition metal migration, void formation and consequently voltage fade in Li-rich cathodes.</jats:p>
収録刊行物
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- Nature Materials
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Nature Materials 23 (6), 818-825, 2024-03-01
Springer Science and Business Media LLC