title: Changes in electronic structure upon lithium insertion into Fe2(SO4)3 and Fe2(MoO4)3 investigated by X-ray absorption spectroscopy.
abstract: Changes in electronic structure upon electrochemical lithium insertion into two iron compounds, namely, rhombohedral Fe2(SO4)3 with a NASICON-type structure and monoclinic Fe2(MoO4)3, were investigated using X-ray absorption spectroscopy (XAS). Fe K-edge and L(III)- and L(II)-edge XAS revealed that the rearrangement of Fe d electrons or rehybridization of Fe d-O p bonding took place accompanied by the reduction of Fe ions upon Li insertion for both samples and that a larger change in spectra was observed in Fe2(SO4)3. In addition, the changes in the electronic structure of the polyanion units XO4(2-) (X = S or Mo) after Li insertion were also investigated by O K-edge and S K-edge or Mo L(III)-edge XAS. The results indicated that the electronic structure around oxygen markedly changed in Fe2(MoO4)3, while no significant change was observed in Fe2(SO4)3.
authors.affiliation: Department of Applied Chemistry, Tokyo Institute of Technology, Tokyo 152-8552, Japan.
authors.forename: Junichi
authors.initials: J
authors.lastname: Shirakawa
authors.forename: Masanobu
authors.initials: M
authors.lastname: Nakayama
authors.forename: Masataka
authors.initials: M
authors.lastname: Wakihara
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Uchimoto
mesh_terms: D004563:Electrochemistry; D004735:Energy Transfer; D005290:Ferric Compounds / Q000737:chemistry*; D058085:Iron Compounds / Q000737:chemistry*; D008094:Lithium / Q000737:chemistry*; D008982:Molybdenum / Q000737:chemistry*; D013052:Spectrometry, X-Ray Emission
chemical_list: D005290:Ferric Compounds; D058085:Iron Compounds; C044659:molybdate; C024823:ferric sulfate; D008982:Molybdenum; D008094:Lithium