nating sphere) comprises 12 other oxide ions. Assuming that any oxygen dimerization occurs between nearest O-O pairs, this gives rise to 12 possible dimer pairs for R 3m NiO 2 . We bring each nearest pair of oxide ions together, with equal and opposite displacements, to a separation of 1.2 Å-corresponding to the bond length of molecular oxygen (O 2 ). A deduplication of symmetry-equivalent configurations is then performed. For each dimer, first 1, then 2 of the 6 nickel ions coordinated to either oxide ion before displacement are selected at random and projected into the spacing between NiO 2 layers by 1 Å to 2 Å. Each of these structures is then subjected to a random displacement of all ions to break symmetry and aid the identification of structural reconstructions, following a normal distribution with a standard deviation of 0.2 Å. This procedure is shown schematically in fig. . Each of the generated structures was then relaxed with hybrid DFT using coarse calculation settings (see computational methods) and their energies compared to understand potential oxygen dimer formation LiNiO 2 at high states of charge.