Uncovering coupled ionic-polaronic dynamics and interfacial enhancement in Li$_x$FePO$_4$
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arXiv
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| Autori principali: | , , , |
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| Natura: | Preprint |
| Pubblicazione: |
2025
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| _version_ | 1866915376809377792 |
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| author | Xie, Fengyu Gao, Yuxiang Wang, Ruoyu Zhong, Zhicheng |
| author_facet | Xie, Fengyu Gao, Yuxiang Wang, Ruoyu Zhong, Zhicheng |
| contents | Understanding and controlling coupled ionic-polaronic dynamics is crucial for optimizing electrochemical performance in battery materials. However, studying such coupled dynamics remains challenging due to the intricate interplay between Li-ion configurations, polaron charge ordering, and lattice vibrations. Here, we develop a fine-tuned machine-learned force field (MLFF) for Li$_x$FePO$_4$ that captures coupled ion-polaron behavior. Our simulations reveal picosecond-scale polaron flips occurring orders of magnitude faster than Li-ion migration, featuring strong correlation to Li configurations. Notably, polaron charge fluctuations are further enhanced at Li-rich/Li-poor phase boundaries, suggesting a potential interfacial electronic conduction mechanism. These results demonstrate the capability of fine-tuned MLFFs to resolve complex coupled transport and provide insight into emergent ionic-polaronic dynamics in multivalent battery cathodes. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2507_05626 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Uncovering coupled ionic-polaronic dynamics and interfacial enhancement in Li$_x$FePO$_4$ Xie, Fengyu Gao, Yuxiang Wang, Ruoyu Zhong, Zhicheng Materials Science Computational Physics Understanding and controlling coupled ionic-polaronic dynamics is crucial for optimizing electrochemical performance in battery materials. However, studying such coupled dynamics remains challenging due to the intricate interplay between Li-ion configurations, polaron charge ordering, and lattice vibrations. Here, we develop a fine-tuned machine-learned force field (MLFF) for Li$_x$FePO$_4$ that captures coupled ion-polaron behavior. Our simulations reveal picosecond-scale polaron flips occurring orders of magnitude faster than Li-ion migration, featuring strong correlation to Li configurations. Notably, polaron charge fluctuations are further enhanced at Li-rich/Li-poor phase boundaries, suggesting a potential interfacial electronic conduction mechanism. These results demonstrate the capability of fine-tuned MLFFs to resolve complex coupled transport and provide insight into emergent ionic-polaronic dynamics in multivalent battery cathodes. |
| title | Uncovering coupled ionic-polaronic dynamics and interfacial enhancement in Li$_x$FePO$_4$ |
| topic | Materials Science Computational Physics |
| url | https://arxiv.org/abs/2507.05626 |