X-ray and neutron diffraction, 57Fe Mِssbauer spectroscopy and X-ray absorption spectroscopy studies of iron-substituted lithium cobaltate

Powdered solids with LiFe0.1Co0.9O2, LiFe0.2Co0.8O2 and LiFe0.2Co0.6Ni0.2O2 compositions have been prepared by ceramic procedures in the presence of excess lithium. The combined refinement of X-ray and neutron diffraction data reveals that cation substitution takes place in the octahedral sites with an almost complete absence of tetrahedrally coordinated iron. The 57Fe Mِssbauer spectra of these solids agree with this model and show a non-random distribution of Fe and Co ions in octahedral sites.