Sustainable society and electric vehicles are facilitated by battery technology; improving battery capacity is one of the social urgent issues today. Transition metal oxide materials are currently used for cathodes of lithium-ion batteries and magnesium rechargeable batteries, facing the intrinsic capacity limit determined by valence change of constituent transition metals. To tackle this problem, I study on strain effect yielded by a nano-domain microstructure in the oxide electrodes, which is expected to unlock large capacity delivered by anionic (e.g., oxygen and sulfur) reduction/oxidation (redox) reaction as well as the conventional cationic reaction.