Manganese oxide as an effective electrode material for energy storage: a review

Efficient materials for energy storage, in particular for supercapacitors and batteries, are urgently needed in the context of the rapid development of battery-bearing products such as vehicles, cell phones and connected objects. Storage devices are mainly based on active electrode materials. Various transition metal oxides-based materials have been used as active materials to produce electrodes. For instance, manganese-based oxides (MnxOy) have been used extensively as an electrode material due to higher specific capacitance, large potential range, and various crystal structures. Manganese (III) oxide (Mn2O3) has not been extensively explored as electrode material despite a high theoretical specific capacity value of 1018 mAh/g and multivalent cations: Mn3+ and Mn4+. Here, we review Mn2O3 strategic design, construction, morphology, and the integration with conductive species for energy storage applications. Improving the performance of Mn2O3-based electrodes requires the formation of nanostructure and blending with electrically-conductive matrices, and adjusting the morphology of the Mn2O3. Some issues of structural design for volume change, poor cyclic stability, characterization and understanding of ions transfer and transport within the Mn2O3-based electrodes are still unanswered.