Abstract The evolution of transition metal oxide cathodes with cycling is governed by a subtle interplay between redox processes and (local) structural distortions. Here, we use first-principles calculations to monitor the electronic and structural evolution of the spinel LiNi0.5Mn1.5O4 (LNMO) cathode at various stages of charge. In its P4332 ordered ground state, redox-active NiO6 octahedra are spatially isolated by redox-inactive Mn4+ cations, providing a clean platform to disentangle local redox and structural phenomena. By combining analyses of magnetic moments, Bader charges, and charge-density difference maps, we show that redox processes are localized on Ni, yet trigger significant transition metal–oxygen rehybridization extending to both Ni–O and Mn–O networks. Changes in oxygen charge are traced to polarization driven by evolving Ni–O bonding, rather than to anion redox activity. Concurrent structural changes include a stepwise volumetric contraction of the NiO6 octahedra...