  Understanding the LiMnPO4/MnPO4 phase transition is of great interest in
order to further improve the electrochemical performance of this cathode
material. Since most of the previously published literature deals with
characterization of chemically delithiated Lix MnPO4, the aim of this study is
to compare and study the composition and structure of the different phases that
are generated upon chemical delithiation of LixMnPO4. Bare and carboncoated
lithium manganese phos-phates are prepared via a combined
coprecipitation-calcination method. Partial delithiation to two different
degrees of delithiation Lix MnPO4 (x = 0.24/0.23 and 0.45) for carbon-coated
and/or bare materials is achieved using an excess of nitro-nium
tetrafluoroborate in acetonitrile. The effect of carboncoating has been also
considered. Standard materials characterization with XRD (X-Ray Diffraction)
and ICPOES (Inductive Coupled Plasma spectrometry and Optical Emission
Spectroscopy) analysis are in accordance with literature data, but further
cerimetric analysis revealed serious deviations, showing differences in the
degree of delithiation to the average degree of oxidation. A structural
characterization of the atomic and electronic local structure of the materials
is also ob-tained using XAS (X-ray Absorption Spectroscopy) technique.
