Fast determination of phases in LixFePO4 using low losses in electron energy-loss spectroscopy

Experimental valence electron energy-loss spectra, obtained on different phases of LixFePO4, are analyzed with first principles calculations based on density functional theory. In the 4-7 eV range, a large peak is identified in the FePO4 spectrum but is absent in LiFePO4, which allows the easy formation of energy filtered images. The intensity of this peak, nonsensitive to the precise orientation of the crystal, is large enough to rapidly determine existing phases in the sample and permit future dynamical studies.