Bi-Functional Oxygen Electrodes Using LaMnO3/LaNiO3 for Rechargeable Metal-Air Batteries

Carbon supported-electrocatalysts are principally used as catalytic layers for air electrodes of metal air batteries. However, these types of air electrodes are problematic because the carbon support can be oxidized to water soluble organic compounds under anodic polarization for a charge process. In this study, we have investigated to use LaNiO3 as a possible electrode material to replace the carbon support because LaNiO3 has both high electric conductivity and high oxygen evolution activity. LaNiO3 was prepared by a reverse homogeneous precipitation method, and then LaMnO3, which is active for oxygen reduction reactions, was successfully loaded onto the LaNiO3 by using a reverse micelle method. LaNiO3 had a much higher stability against anodic polarization as compared to carbon support. The LaMnO3/LaNiO3 composite electrode showed excellent bi-functional oxygen reduction/evolution activity in an alkaline solution and this makes it a highly potential candidate for use in rechargeable metal-air batteries. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3562564] All rights reserved.