The oxidation of the oxide ions near the vacancy in the nickel layer is not surprising. These oxide ions can be considered uncoordinated relative to the other oxide ions (ONi 2 V 4 as opposed to ONi 3 V 3 where V indicates a vacant site). These configurations stabilize oxygen holes upon delithiation because they host orphaned O 2p orbitals and exhibit a lower Madelung potential, leading to a lower hole localization energy, rendering them easily oxidizable . The relative stability of the structure containing the molecular oxygen-like dimer suggests that these holes can be stabilized by dimerizing. To provide further evidence supporting the stabilization of the dimer system compared to a structure with a vacant site in the nickel layer where no dimerization occurs, we conducted two additional calculations. These calculations represent the lowest energy configurations for a nickel vacancy structure with an unstable dimer, and an oxygen-dimer structure from which the migrated nickel atom has been removed. Our results confirm that the structure containing the oxygen dimer is more stable, with an energy difference of 0.4 eV.