BI-FUNCTIONAL OXYGEN-ELECTRODE USING LARGE SURFACE-AREA LA1-XCAXCOO3 FOR RECHARGEABLE METAL-AIR BATTERY

In order to develop an air electrode to be used for rechargeable metal-air batteries, gas-diffusion type carbon-based electrodes have been tested for the electrochemical reduction and evolution of oxygen. The electrode, loaded with a large surface area of La0.6Ca0.4CoO3 catalyst was found to show high bifunctional performance, i.e., 3000 mA/cm2 (oxygen reduction) and 1000 mA/cm2 (oxygen evolution) at −125 and +700 mV vs. Hg/HgO, respectively, in 30 w/o KOH at 25°C. The oxide catalyst is considered to decompose effectively HO2−, an intermediate appearing in both oxygen reduction and oxygen evolution reactions. The air electrode was stable for 100 cycles of charge-discharge test at a current density of 100 mA/cm2. © 1990, The Electrochemical Society, Inc. All rights reserved.