The oxidation of a carbon binder that occurred during a charge in a carbon-MnO2 air electrode for a Li-air battery resulted in an excessively high charge potential of 4.2 V. The air electrode activity for the Li-air battery was studied on various metals or metal oxides and the mixture of Pd and MnO2 shows the high activity to oxidation and reduction of Li to form Li2O2 or Li2O, respectively. Although the discharge capacity decreased, the application of Pd/MnO2 without a carbon binder for the air electrode is effective to decrease the charge potential and to improve the energy efficiency from 60 to 89%. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3481762] All rights reserved.