New insights on the effects of surface facets and calcination temperature on electrochemical properties of MnCo2O4 as bifunctional oxygen electrocatalyst in zinc-air batteries

Metal-air rechargeable batteries are being studied as an alternative to lithium-ion batteries. MnCo2O4 as a ternary mixed metal oxide appeared as a promising oxygen electrocatalyst in metal-air batteries due to relatively high electrocatalytic activity and electronic conductivity. The effects of surface facets and calcination temper-ature on the electrochemical properties of MnCo2O4 in zinc-air batteries are investigated experimentally and theoretically. The results show that by increasing calcination temperature, the surface facet is changing from the high index {112} to the low index {110}. Concurrently, the oxygen vacancy concentration rises with calcination temperature. Electrochemical results and first principle calculations indicate that the oxygen-deficient {110} facet has superior electrochemical activity over the {112} facet in terms of oxygen evolution reaction and oxygen reduction reaction. These results are essential for designing high performance spinel structured electrocatalyst materials.

Automated summary

Metal-air rechargeable batteries are being studied as an alternative to lithium-ion batteries, and MnCo2O4 is found to be a promising oxygen electrocatalyst in these batteries. The effects of surface facets and calcination temperature on the electrochemical properties of MnCo2O4 in zinc-air batteries are investigated experimentally and theoretically. The results show that the {110} facet of MnCo2O4 has superior electrochemical activity compared to the {112} facet, which is important for designing high performance electrocatalyst materials.