This distortion (∆d Mn-O = 0.06 Å) is minor compared to the pronounced JT distortion for Mn 3+ observed in LMO spinel, with ∆d Mn-O = 0.28 Å. 85 HSE06 where the Ni contribution is increased (from 24% -34%) (Table ). This phenomenon is also observed in other compounds such as LiNiO 2 where oxygens are bonded to late-3d metals with increased crystal-field splitting. This would decrease the tendency towards hole localisation and redox processes are likely to involve Ni-O hybridised bands strong in O character. However, on a per-atom basis, the contribution from Ni states is at least two times higher than that of O at VBM. This is consistent with experimental observations where Ni was shown to be redox-active. The CBM has a greater proportion of Mn 3d states than O 2p states with both functionals.