Although there exist two experimental Li 2 NiO 2 phases with distinctive structural framework, we simply use the minimum separations from Li 2 NiO 3 to perform the search (Table ). This is an example of an explorative search, where the structural information from a relevant composition is used to generate sensible random structures. Regardless of the oxidation states on Ni, the minimum separations from different (Li x Ni y O z ) compositions set constraints that avoid cation-cation and anion-anion being to close, hence the separations do not need to be exact values to achieve efficient searching. Figure shows the structures optimized using the PBEsol+U and SCAN functionals.