Mixed Metal Oxide Catalysts for Rechargeable Lithium-Air Batteries

Abstract

In this report, the preparation, characterization and electrochemical performance of manganese and cobalt containing mixed metal-oxide catalysts for use in lithium-air cells was investigated. Samples with several manganese/cobalt ratios were prepared by a combustion synthesis method and mixed with a high surface-area carbon to form cathodes. All catalysts resulted in a reduction in charge overpotential with respect to a carbon cathode, but the relative performance of the catalysts may depend on the discharge product. To ensure a fair comparison of the materials, catalysts were further evaluated for the charge overpotential to decompose Li2O2. In this test, all the catalysts exhibited a similar recharge potential of about 3.85V at a current density of 0.05mA/cm2 which is ~150mV lower than a plain carbon electrode. Varying the Mn to Co ratio did not have a significant effect on the charge overpotential for the pre-loaded electrodes at lower current density, suggesting that the catalyst efficiency is not a limiting factor in this system.