This file includes the VASP files for all the calculations used in the paper “Appraisal of calcium ferrites as cathodes for calcium rechargeable batteries: DFT, synthesis, characterization and electrochemistry of Ca4Fe9O17” (DOI: 10.1039/c9dt04688g) The files are organized in oxides: CaFe2O4, Ca4Fe9O17, CaFe3O5 and CaFe4O6. Energies for the voltage calculations can be found in the directories x1 and x0. The extremes for the NEB calculations are in the directories denoted as “files”