High resolution x-ray absorption and emission spectroscopy of LixCoO2 single crystals as a function delithiation. (31st January 2017)

• Record Type: Journal Article
• Authors: Simonelli, L; Paris, E; Iwai, C; Miyoshi, K; Takeuchi, J; Mizokawa, T; Saini, N L
• Is Part Of: Journal of physics. Volume 29:Number 10(2017)
• Publication Date: 2017-01-31
• Subjects: x-ray emission spectra and fluorescence -- lithium-ion batteries -- x-ray absorption spectra -- electronic structure; Condensed matter -- Periodicals; Matière condensée -- Périodiques; Vaste stoffen; Vloeistoffen; Natuurkunde; Electronic journals; Computer network resources; 530.4105
• DOI: 10.1088/1361-648X/aa574d
• Languages: English
• ISSNs: 0953-8984

Abstract

Abstract: The effect of delithiation in Li x CoO2 is studied by high resolution Co K-edge x-ray absorption and x-ray emission spectroscopy. Polarization dependence of the x-ray absorption spectra on single crystal samples is exploited to reveal information on the anisotropic electronic structure. We find that the electronic structure of Li x CoO2 is significantly affected by delithiation in which the Co ions oxidation state tending to change from 3+ to 4+. The Co intersite (intrasite) 4 p –3 d hybridization suffers a decrease (increase) by delithiation. The unoccupied 3 d t 2 g orbitals with a 1 g symmetry, containing substantial O 2 p character, hybridize isotropically with Co 4 p orbitals and likely to have itinerant character unlike anisotropically hybridized 3 d e g orbitals. Such a peculiar electronic structure could have significant effect on the mobility of Li in Li x CoO2 cathode and hence the battery characteristics.