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| Format: | Preprint |
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2025
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| Online-Zugang: | https://arxiv.org/abs/2505.01251 |
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| _version_ | 1866918146093350912 |
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| author | Fajardo, Galo J. Paez Dogaru, Daniela Banerjee, Hrishit Ans, Muhammad Ogley, Matthew J. W. Majherova, Veronika McClelland, Innes Hayashida, Shohei Puphal, Pascal Isobe, Masahiko Keimer, Bernhard Thakur, Pardeep K. Lee, Tien-Lin Grinter, Dave C. Ferrer, Pilar Cussen, Serena A. Hepting, Matthias Piper, Louis F. J. |
| author_facet | Fajardo, Galo J. Paez Dogaru, Daniela Banerjee, Hrishit Ans, Muhammad Ogley, Matthew J. W. Majherova, Veronika McClelland, Innes Hayashida, Shohei Puphal, Pascal Isobe, Masahiko Keimer, Bernhard Thakur, Pardeep K. Lee, Tien-Lin Grinter, Dave C. Ferrer, Pilar Cussen, Serena A. Hepting, Matthias Piper, Louis F. J. |
| contents | Describing Li-ion battery positive electrodes in terms of distinct transition metal or oxygen redox regimes can lead to confusion in understanding metal-ligand hybridisation, oxygen dimerisation, and degradation. There is a pressing need to study the electronic structure of these materials and determine the role each cation and anion plays in charge compensation. Here, we employ transition metal L-edge X-ray Resonance Photoemission Spectroscopy in conjunction with Single Impurity Anderson models, Self-consistent Real Space Multiple Scattering spectral simulations, and Dynamical Mean-Field theory calculations to directly evaluate the redox mechanisms in (de-)lithiated battery electrodes. This approach reconciles the redox description of two canonical cathodes -- LiMn$_{0.6}$Fe$_{0.4}$PO$_{4}$ and LiNiO$_{2}$ -- in terms of varying degrees of charge transfer using the established Zaanen-Sawatzky-Allen framework, common to condensed matter physics. In LiMn$_{0.6}$Fe$_{0.4}$PO$_{4}$, the absence of charge transfer means capacity arises due to the depopulation of metal $\textit{3d}$ states, i.e. conventional metal redox. Whereas, in LiNiO$_{2}$, charge transfer dominates and redox occurs through the formation and elimination of ligand hole states. This work clarifies the role of oxygen in Ni-rich system and provides a framework to explain how capacity can be extracted from oxygen-dominated states in highly covalent systems without needing to invoke dimerisation. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2505_01251 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Direct Evidence of Metal-Ligand Redox in Li-ion Battery Positive Electrodes Fajardo, Galo J. Paez Dogaru, Daniela Banerjee, Hrishit Ans, Muhammad Ogley, Matthew J. W. Majherova, Veronika McClelland, Innes Hayashida, Shohei Puphal, Pascal Isobe, Masahiko Keimer, Bernhard Thakur, Pardeep K. Lee, Tien-Lin Grinter, Dave C. Ferrer, Pilar Cussen, Serena A. Hepting, Matthias Piper, Louis F. J. Materials Science Describing Li-ion battery positive electrodes in terms of distinct transition metal or oxygen redox regimes can lead to confusion in understanding metal-ligand hybridisation, oxygen dimerisation, and degradation. There is a pressing need to study the electronic structure of these materials and determine the role each cation and anion plays in charge compensation. Here, we employ transition metal L-edge X-ray Resonance Photoemission Spectroscopy in conjunction with Single Impurity Anderson models, Self-consistent Real Space Multiple Scattering spectral simulations, and Dynamical Mean-Field theory calculations to directly evaluate the redox mechanisms in (de-)lithiated battery electrodes. This approach reconciles the redox description of two canonical cathodes -- LiMn$_{0.6}$Fe$_{0.4}$PO$_{4}$ and LiNiO$_{2}$ -- in terms of varying degrees of charge transfer using the established Zaanen-Sawatzky-Allen framework, common to condensed matter physics. In LiMn$_{0.6}$Fe$_{0.4}$PO$_{4}$, the absence of charge transfer means capacity arises due to the depopulation of metal $\textit{3d}$ states, i.e. conventional metal redox. Whereas, in LiNiO$_{2}$, charge transfer dominates and redox occurs through the formation and elimination of ligand hole states. This work clarifies the role of oxygen in Ni-rich system and provides a framework to explain how capacity can be extracted from oxygen-dominated states in highly covalent systems without needing to invoke dimerisation. |
| title | Direct Evidence of Metal-Ligand Redox in Li-ion Battery Positive Electrodes |
| topic | Materials Science |
| url | https://arxiv.org/abs/2505.01251 |