Local structures in mixed LixFe1-yMyPO4 (M=Co,Ni) electrode materials

A1 Journal article (refereed)


Internal Authors/Editors


Publication Details

List of Authors: K. Jalkanen, J. Lindén, M. Karppinen
Publisher: Elsevier
Place: Earth
Publication year: 2015
Journal: Journal of Solid State Chemistry
Journal acronym: J. Solid State Chem
Volume number: 230
Issue number: 1
Start page: 404
End page: 410
eISSN: 0022-4596


Abstract

We employ Fe-57 Mössbauer spectroscopy as a local tool to probe electrical environments of Fe2+ and Fe3+ at different lithiation (x) and cation-substitution (y) levels in Li xFe1-yMyPO4/C (M= Co, Ni) Li-ion battery electrode materials. Upon delithiation the local environment of Fe3+ remains unaffected for the
parent y=0 system due to the LiFePO4/FePO4 phase separation, whereas for y>0 changes in the electrical environment are seen for Fe3+. When the Fe2+ /Fe3+ redox couple is partially-delithiated, a decreasing quadrupole splitting value is observed for Fe3+ with increasing y, implying a more symmetric electrical environment. The increasing concentration of the Co2+ /Ni2+ substituent introduces increasing
amounts of Li atoms in the Fe3+ -containing phase, and these nearest-neighbor Li atoms are suspected to cause the changes seen in the local environment of Fe3+.


Keywords

57Fe Mössbauer spectroscopy

Last updated on 2020-18-01 at 03:57