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arXiv · 1505.01612

Electronic structure of Li$_{1+x}$[Mn$_{0.5}$Ni$_{0.5}$]$_{1-x}$O$_2$ studied by photoemission and x-ray absorption spectroscopy

Y. Yokoyama·D. Ootsuki·T. Sugimoto·H. Wadati·J. Okabayashi·Xu Yang·Fei Du·Gang Chen·T. Mizokawa
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Abstract

We have studied the electronic structure of Li$_{1+x}$[Mn$_{0.5}$Ni$_{0.5}$]$_{1-x}$O$_2$ ($x$ = 0.00 and 0.05), one of the promising cathode materials for Li ion battery, by means of x-ray photoemission and absorption spectroscopy. The results show that the valences of Mn and Ni are basically 4+ and 2+, respectively. However, the Mn$^{3+}$ component in the $x$ = 0.00 sample gradually increases with the bulk sensitivity of the experiment, indicating that the Jahn-Teller active Mn$^{3+}$ ions are introduced in the bulk due to the site exchange between Li and Ni. The Mn$^{3+}$ component gets negligibly small in the $x$ = 0.05 sample, which indicates that the excess Li suppresses the site exchange and removes the Jahn-Teller active Mn$^{3+}$.

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Y. Yokoyama, D. Ootsuki, T. Sugimoto, H. Wadati, J. Okabayashi, Xu Yang, Fei Du, Gang Chen, T. Mizokawa. 2015-05-07. Electronic structure of Li$_{1+x}$[Mn$_{0.5}$Ni$_{0.5}$]$_{1-x}$O$_2$ studied by photoemission and x-ray absorption spectroscopy. https://doi.org/10.1063/1.4927239

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