Thin‐film electrodes that are deposited either by electron‐beam evaporation or radio‐frequency sputtering show electrochemical activity between 4 and 5 V vs. metallic lithium. This behavior is significantly different to that expected from a standard spinel electrode. The unusual electrochemical behavior of thin‐film electrodes can be accounted for in terms of a structural model that may be considered as an intergrowth of two spinels, and , where 8a and 8b refer to tetrahedral sites, and 16c and 16d refer to octahedral sites of the space group Fd3m.