The compositions of the phases that are found to be close to the convex hull within a 50 meV per atom range is shown in Table , where V a is calculated average voltage, ∆V is the volume change after delithiation and E h is the distance to the convex hull, S c is the theoretical specific capacity, and S e is the specific energy computed from on V a and S c . Our search has also reproduced the anti-perovskite Li 2 FeSO phase (Fig. ) that was reported previously , and it is predicted to be on the convex hull (e.g. thermaldynamically stable) at 0 K. A previous DFT study predicts Li 2 FeSO to be metastable and would decompose into Li 2 FeO 2 , FeS and Li 2 S 24 , whereas it is found to be stable here. This difference is likely to be caused by the methodology of treating transition metals in different type of compounds. In that work, the PBE/PBE+U calculations are mixed , where the Hubbard-correction for Fe is only applied to oxide/oxysulphide phases with the energies adjusted using the correction factors from the Materials Project . In this approach, the PBE+U correction factor is supposed to be calibrated for reproducing oxide formation energies involving metallic Fe and O 2 . Applying the same term to oxysulphides would introduce systematic errors and affection the reaction energy of forming oxysulphides from oxide and sulphides. However, we found that the data and correction factors from Materials Project does not reproduce the formation energy of iron oxides using the methodologies that are referred to . With refitted parameters, the PBE/PBE+U mixing approach overly favours FeS formation which could seriously affect the results. More discussion can be found in the electronic sup-Table Compositions that are close to the convex hull found in the search and their computed average voltages and theoretical capacities. Symbols: V a is calculated average voltage; ∆V is the volume change after delithiation; E h is the distance to the convex hull; S c is the specific capacity; S e is the specific energy.