Electronic structure of phospho-olivines Li(x)FePO4 (x = 0, 1) from soft-x-ray-absorption and -emission spectroscopies.
The electronic structure of the phospho-olivine Li(x)FePO4 was studied using soft-x-ray-absorption (XAS) and emission spectroscopies. Characteristic changes in the valence and conduction bands are observed upon delithation of LiFePO4 into FePO4. In LiFePO4, the Fe-3d states are localized with little overlap with the O-2p states. Delithiation of LiFePO4 gives stronger hybridization between Fe-3d states and O-2p states leading to delocalization of the O-2p states. The Fe L-edge absorption spectra yield "fingerprints" of the different valence states of Fe in LiFePO4 and FePO4. Resonant soft-x-ray-emission spectroscopy at the Fe L edge shows strong contributions from resonant inelastic soft x-ray scattering (RIXS), which is described using an ionic picture of the Fe-3d states. Together the Fe L-edge XAS and RIXS study reveals a bonding character of the Fe 3d-O2p orbitals in FePO4 in contrast to a nonbonding character in LiFePO4.
Augustsson
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A
Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
Zhuang
G V
GV
Butorin
S M
SM
Osorio-Guillén
J M
JM
Dong
C L
CL
Ahuja
R
R
Chang
C L
CL
Ross
P N
PN
Nordgren
J
J
Guo
J-H
JH