2018/09/30 by Zengqing Zhuo, Chaitanya Das Pemmaraju, John Vinson +12 · 1 citation
Physics and Astronomy · #physics.chem-ph #cond-mat.mtrl-sci #physics.app-ph
paper · pdf · doi:10.1021/acs.jpclett.8b02757
published as The Journal of Physical Chemistry Letters 9, 6378-6384 (2018) · 25 pages, 4 figures, plus 11 pages of Supplementary Information with 4 figures
arxiv created 2018/10/17 · arxiv updated 2018/11/15
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.