Preparation of MnO2-Cr2O3 mesoporous oxide and its application for an active and reversible air catalyst for Li-O2 batteries

Preparation of highly porous MnO2 and Cr2O3 with regular structure was investigated in this study by using hard template method. Cr2O3 nanoarchitects with regular pore structure and α-MnO2 with porous nanosheet were successfully prepared. By mixing with single wall carbon nanotube (SWCNT), application of MnO2, Cr2O3 nano architects (Mn-Cr oxides supported SWCNT) was studied as active air electrode for Li-O2 battery which is now expecting as a new rechargeable battery with large capacity. It was found that the synergy effects between two mesoporous metal oxides with SWCNT resulted in excellent electrochemical properties of air electrode. Prepared Mn-Cr oxide supported SWCNT can sustain stable charge and discharge capacity up to 150 cycles with 500 mAh/g without capacity degradation indicating outstanding catalytic activity for oxygen reduction and evolution reaction (ORR/OER). Consecutive cyclic voltammetry tests also showed excellent reversibility of formation and decomposition of reaction products of Li2O2. This could be resulted from large pore volume and ordered structure of Cr2O3, MnO2/SWCNT air electrode.