Fast determination of phases in LiFePO4 using low losses in electron energy-loss spectroscopy

Experimental valence electron energy loss spectra (VEELS), up to the Li K edge, obtained on different phases of LixFePO4 are compared to first principles calculations using the density functional code WIEN2k. In the 4-7 eV range, a large peak is identified in the FePO4 spectrum, but is absent in LiFePO4, which could allow the easy formation of energy filtered images. The intensity of this peak, non sensitive to the precise orientation of the crystal, is large enough to rapidly determine existing phases in the sample and permit future dynamical studies. Solid solution and two-phases regions are also differentiated using Fe M2,3 / Li K edges.