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arXiv · 1809.08292

Spectroscopic Signature of Oxidized Oxygen States in Peroxides

Zengqing Zhuo·Chaitanya Das Pemmaraju·John Vinson·Chunjing Jia·Brian Moritz·Ilkyu Lee·Shawn Sallies·Qinghao Li·Jinpeng Wu·Kehua Dai·Yi-de Chuang·Zahid Hussain·Feng Pan·Thomas P. Devereaux·Wanli Yang
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Abstract

Recent debates on the oxygen redox behaviors in battery electrodes have triggered a pressing demand for the reliable detection and understanding of non-divalent oxygen states beyond conventional absorption spectroscopy. Here, enabled by high-efficiency mapping of resonant inelastic X-ray scattering (mRIXS) coupled with first-principles calculations, we report distinct mRIXS features of the oxygen states in Li2O, Li2CO3, and especially, Li2O2, which are successfully reproduced and interpreted theoretically. mRIXS signals are dominated by valence-band decays in Li2O and Li2CO3. However, the oxidized oxygen in Li2O2 leads to partially unoccupied O-2p states that yield a specific intra-band excitonic feature in mRIXS. Such a feature displays a specific emission energy in mRIXS, which disentangles the oxidized oxygen states from the dominating transition-metal/oxygen hybridization features in absorption spectroscopy, thus providing critical hints for both detecting and understanding the oxygen redox reactions in transition-metal oxide based battery materials.

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Zengqing Zhuo, Chaitanya Das Pemmaraju, John Vinson, Chunjing Jia, Brian Moritz, Ilkyu Lee, Shawn Sallies, Qinghao Li, Jinpeng Wu, Kehua Dai, Yi-de Chuang, Zahid Hussain, Feng Pan, Thomas P. Devereaux, Wanli Yang. 2018-09-21. Spectroscopic Signature of Oxidized Oxygen States in Peroxides. https://doi.org/10.1021/acs.jpclett.8b02757

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