Concentrated solar power plant needs to be equipped with large-scale high-temperature heat storage module. Metal oxides can store and release heat through reversible redox reaction. Manganese oxides is non-toxic and cheap, showing great potential for applying in solar power plant, but it displays poor reversibility. Here, a manganese-based oxides with high reversibility by deep eutectic solvent (DES) ionic thermal synthesis was proposed, and effects of synthesis parameters and iron doping on heat storage performance were studied. MnCO₃, as the raw material, was used to produce manganese oxides by ionic thermal decomposition at high temperature and released CO₂, which could also form abundant pore structure, providing great channels for oxygen transmission and diffusionfor redox. Although this Mn₂O₃ synthesis method showed better reactivity than commercial Mn₂O₃, its oxidation rate was low. It is worth noting that oxidation rate of manganese iron oxide doped with 20% Fe, synthesized at 150 ℃, was fast. Its heat storage density reached 300.66 J/g, and reversibility of the reaction was the best, which could realize long-term stable cycle. Our results demonstrated that ionic thermal synthesis can increase the lattice oxygen ratio in manganese oxides, promoting migration of oxygen vacancies, and further improving reversibility and cyclic stability.