Abstract
A method for durability testing of solid oxide cell electrodes in current-switching operation is presented. The method provides both electrochemical and microstructural information by using multiple symmetrical cells connected in series. Electrochemical impedance spectroscopy measurements were done periodically during life tests of (La0.8Sr0.2)0.98MnO3-Zr0.84Y0.16O2 (LSM-YSZ) symmetrical cells at 800°C in air with a current of 0.5 or 1.5Acm-2 switched every 30 minutes. By periodically removing cells from the circuit during the life test, microstructural changes due to current were observed at different stages. Focused Ion Beam-Scanning Electron Microscope (FIB-SEM) tomographic measurements of electrode microstructure were done on cells with different times at current. Silver, from current collectors used in the tests, was found to migrate into the electrodes near the YSZ electrolyte during fuel cell operation. The silver content increased with time at current and presumably explained the observed steady increase in polarization resistance.