For a target vacancy concentration of [V O ] = 1%, Figure shows the pO 2 vs temperature diagram for oxides within X < 0.05 eV/at from the convex hull, using the ML screening of the MP data (cf. Section 2.6). This concentration is generally considered as a demarcation between the dilute, defect-like, and concentrated, alloy like, limits of non-stoichiometric materials, but a similar analysis can be made for any value of [V O ]. Desirable process conditions are indicated in Figure for Solid Oxide Fuel Cells (SOFC) , Thermochemical Energy Storage (TCES) , and STCH , using the reduction step for the latter two. A spreadsheet with the oxides falling into the respective regions of interests is included in the SI. All three applications depend crucially on the formation of O vacancies, 101 although there are of course other materials considerations that we do not address here. Therefore, the present screening should give valuable insights about potential candidate materials at least for the aspect of O deficient off-stoichiometry.