Structural Deformations During Cycling of the Conversion Cathode Nanocomposite Based on FeF3

The data on the dynamics of structural changes in the composite cathode material based on iron(III) fluoride studied by the operando synchrotron X-ray spectroscopy and diffraction combined with the density functional theory (DFT) are reported. Based on the FeF3 structure determined by X-ray crystallography the crystal structure of LixFeF3 for 0 < x < 0.5 is modeled by the geometry optimization. The crystal structure models for 0.5 < x < 1 are predicted using the evolutionary algorithms. The Fe K-edge X-ray absorption spectra are calculated for these models and compared with the experimental data.