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Updated: May 8, 2026

Tuning Oxide Properties by Oxygen Vacancy Control During Growth and Annealing
Published on: June 9, 2023
Role of oxygen holes in Li(x)CoO(2) revealed by soft X-ray spectroscopy
T Mizokawa1, Y Wakisaka, T Sudayama
1Department of Physics and Department of Complexity Science and Engineering, University of Tokyo, Chiba 277-8561, Japan.
Abstract:
The fundamental electronic structure of the widely used battery material Li(x)CoO(2) still remains a mystery. Soft x-ray absorption spectroscopy of Li(x)CoO(2) reveals that holes with strong O 2p character play an essential role in the electronic conductivity of the Co(3+)/Co(4+) mixed valence CoO(2) layer. The oxygen holes are bound to the Co(4+) sites and the Li-ion vacancy, suggesting that the Li-ion flow can be stabilized by oxygen hole back flow. Such an oxygen hole state of Li(x)CoO(2) is unique among the various oxide-based battery materials and is one of the key ingredients to improving their electronic and Li-ion conductivities.
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