The decomposition reaction of H2O2 aqueous solutions (H2O2 -> H2O + 1/2O(2)) catalyzed by transition metal oxide powders has been compared with the charging voltage of nonaqueous Li-O-2 cells containing the same catalyst. An inverse linear relationship between Ln k (rate constant for the H2O2 decomposition) and the charging voltage has been found, despite differences in media and possible mechanistic differences. The results suggest that the H2O2 decomposition may be a reliable, useful, and fast screening tool for materials that promote the charging process of the Li-O-2 battery and may ultimately give insight into the charging mechanism. (C) 2010 The Electrochemical Society. [DOI: 10.1149/1.3494045] All rights reserved.