Electronic states in oxidized Na x CoO 2 as revealed by X-ray absorption spectroscopy coupled with ab initio calculation
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Abstract
Layered cobalt oxides are promising cathode materials for sodium ion secondary batteries (SIBs). By combined study of the X-ray absorption spectroscopy (XAS) around the O K-edge and ab initio calculation, we investigated the electronic state of the NaxCoO2 with different oxidization state, i.e, in O3-Na0.91CoO2 (CoO2−0.91) and P2-Na0.66CoO2 (CoO2−0.66). The O K-edge spectra in the pre-edge (529–536 eV) region shows significant change with oxidization of NaxCoO2. In O3-Na0.91CoO2, the spectra shows an intense band (B band) at 531 eV. In P2-Na0.66CoO2, the spectral weight of the B band increases and a new band (A band) appears at 530 eV. These spectral changes are qualitatively reproduced by the calculated partial density of states (pDOSs) of O3-NaCoO2 and P2-Na1/2CoO2. These results indicate that the electrons are partially removed from the O 2p state with oxidization of NaxCoO2.
Journal
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- Journal of power sources
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Journal of power sources 384 156-159, 2018-04
Elsevier
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Details 詳細情報について
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- CRID
- 1050001202641859712
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- NII Article ID
- 120007133899
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- NII Book ID
- AA00705373
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- ISSN
- 03787753
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- HANDLE
- 2241/00153368
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- Text Lang
- en
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- Article Type
- journal article
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- Data Source
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- IRDB
- CiNii Articles