Investigating the phase diagram and the local disorder of La2NiO4-xF2x intercalation cathodes for Fluorine Ion Batteries

We aim at investigating the average and local structure of La2NiO4-xF2x intercalation cathodes for Fluoride ion batteries (FIBs) as alternatives to Li batteries. PXRD patterns will be collected in suitable x (0≤x≤1.5) and T (100≤T≤600) ranges, so encompassing their operating range. The data will be analyzed using Rietveld and PDF analysis, flanked by BVS and DFT calculations. All expertizes (synthesis, data collecting and analysis, DFT calculations) are present in the proposing team. We expect to map the structure of La2NiO4-xF2x samples as a function of x and T at different length scales spanning from the local order to the average structure. This study will establish the local distortions (tilting of octahedral, possible Ni-off centring) and the anion distribution in these compounds in different thermodynamic conditions and is a prerequisite also to understand the atomistic mechanisms of F- diffusion and intercalation within this family of compounds.