Elucidation of Active Oxygen Sites upon Delithiation of Li3IrO4

Transformational increases in the storage capacity of battery cathodes could be achieved by tapping into the redox activity at oxide ligands in addition to conventional transition metal couples. However, the key signatures that govern such lattice oxygen redox (LOR) have not been ascertained. Li3IrO...

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Bibliographic Details
Published in:ACS energy letters 2020-12, Vol.6 (1)
Main Authors: Li, Haifeng, Perez, Arnaud J., Taudul, Beata, Boyko, Teak D., Freeland, John W., Doublet, Marie-Liesse, Tarascon, Jean-Marie, Cabana, Jordi
Format: Article
Language:English
Subjects:
Electrical energy
INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
Oxidation
Oxide
Redox reactions
Transition metals
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Summary:Transformational increases in the storage capacity of battery cathodes could be achieved by tapping into the redox activity at oxide ligands in addition to conventional transition metal couples. However, the key signatures that govern such lattice oxygen redox (LOR) have not been ascertained. Li3IrO4 has the largest reversible LOR, rendering it a unique model system. Here, X-ray spectroscopy and computational simulations reveal that LOR in Li3IrO4 is selectively compensated via O sites with three lone pairs, which are activated by Li/Ir disorder. The two-electron LOR can be reversed to regenerate the initial state without unlocking competing bulk reactions observed in many other compounds. We uncover an intricate interplay between stoichiometry, O coordination, and nonbonding states in LOR and pinpoint spectroscopic signatures. This interplay is indispensable for designing materials with 3d metals that fulfill the promise of LOR to overcome the bottlenecks of current cathodes for future implementation in practical batteries.
ISSN:2380-8195
2380-8195