Synthesis And Electrochemical Properties Of Mn-based Cathode Catalysts For Metal-Air Batteries

Metal-air batteries have been known as one kind of promising new energy and have been widely used for electric cars,mobile phones and other fields,which can be attributed to high power density and environment friendly.The cathode catalysts performance plays an important role in determining the activity of metal-air batteries.It is necessary to develop catalysts with high activity for improving the cathode performance.In this paper,we prepared Mn-based catalysts with an aerosol-spray approach and investigated their electrochemical properties.1.Support-free porous Mn2O3 was synthesized by a facile aerosol-spray approach.Mn2O3 exhibits good oxygen reduction reaction(ORR)activity that is comparable to commercial Pt/C.Mn2O3 also shows notably higher activity than other Mn-based oxides,such as Mn3O4 and MnO2.Furthermore,the porous Mn2O3 demonstrates considerable stability and good methanol tolerance in alkaline media.2.MnCo2O4 was prepared by an aerosol-spray approach and the oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)activities of MnCo2O4 were systematically investigated.In OER tests,MnCo2O4 achieves a small overpotential at 10 mA/cm2(0.40V),which is close to 0.39 V exhibited by Co3O4.In ORR tests,at-3 mA/cm2 MnCo2O4(0.80 V vs RHE)displays high ORR activity comparable with Mn2O3(0.82 V).Moreover,the electron transfer number of ORR is close to 4e,which turns out that oxygen is mainly reduced to hydroxyl with the help of MnCo2O4.