Correlation between the O 2p Orbital and Redox Reaction in LiMn0.6Fe0.4PO4 Nanowires Studied by Soft X‐ray Absorption |
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| Authors: | Dr Daisuke Asakura Dr Eiji Hosono Dr Masashi Okubo Dr Yusuke Nanba Dr Haoshen Zhou Dr Per‐Anders Glans Dr Jinghua Guo |
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| Institution: | 1. Research Institute for Energy Conservation, National Institute of Advanced Industrial Science and Technology (AIST), Ibaraki, Japan;2. Department of Chemical System Engineering, School of Engineering, The University of Tokyo, Tokyo, Japan;3. INAMORI Frontier Research Center, Kyushu University, Fukuoka, Japan;4. Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California, USA |
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| Abstract: | The changes in the electronic structure of LiMn0.6Fe0.4PO4 nanowires during discharge processes were investigated by using ex situ soft X‐ray absorption spectroscopy. The Fe L ‐edge X‐ray absorption spectrum attributes the potential plateau at 3.45 V versus Li/Li+ of the discharge curve to a reduction of Fe3+ to Fe2+. The Mn L ‐edge X‐ray absorption spectra exhibit the Mn2+ multiplet structure throughout the discharge process, and the crystal‐field splitting was slightly enhanced upon full discharge. The configuration‐interaction full‐multiplet calculation for the X‐ray absorption spectra reveals that the charge‐transfer effect from O 2p to Mn 3d orbitals should be considerably small, unlike that from the O 2p to Fe 3d orbitals. Instead, the O K‐edge X‐ray absorption spectrum shows a clear spectral change during the discharge process, suggesting that the hybridization of O 2p orbitals with Fe 3d orbitals contributes essentially to the reduction. |
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| Keywords: | cathode materials lithium-ion batteries olivine redox reactions soft X-ray absorption spectroscopy |
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