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Ceramic synthesis of disordered lithium rich oxyfluoride materialsJean-Marcel Ateba Mba,
Iztok Arčon,
Gregor Mali,
Elena Tchernychova,
Ralf Witte,
Robert Kruk,
Miran Gaberšček,
Robert Dominko, 2020, original scientific article
Abstract: Disordered lithium-rich transition metal oxyfluorides with a general formula Li1þxMO2Fx (M being a transition
metal) are gaining more attention due to their high specific capacity which can be delivered from the facecentered
cubic (fcc) structure. The most common synthesis procedure involves use of mechanosynthesis. In
this work, ceramic synthesis of lithium rich iron oxyfluoride and lithium rich titanium oxyfluoride are reported.
Two ceramic synthesis routes are developed each leading to the different level of doping with Li and F and
different levels of cationic disorder in the structure. Three different Li1þxMO2Fx samples (x ¼ 0.25, 0.3 and 1) are
compared with a sample prepared by mechanochemical synthesis and non-doped LiFeO2 with fcc structure. The
obtained lithium rich iron oxyfluoride are characterized by use of M€ossbauer spectroscopy, X-ray absorption
spectroscopy, NMR and TEM. Successful incorporation of Li and F have been confirmed and specific capacity that
can be obtained from the samples is in the correlation with the level of disorder introduced with doping,
nevertheless oxidation state of iron in all samples is very similar. Conclusions obtained from lithium rich iron
oxyfluoride are validated by lithium rich titanium oxyfluoride.
Keywords: Lithium batteries
Face centered-cubic
Oxyfluoride
Li-rich
Disorder
Published in RUNG: 05.06.2020; Views: 5241; Downloads: 0
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