The Electrochemical Performance of LSM with A-site Non-Stoichiometry under Cathodic Polarization

The electrochemical performance of (La0.8Sr0.2)xMnO3 (x=1.0, 0.95, 0.9) electrodes with YSZ electrolyte has been investigated as a function of the A-site non-stoichiometry. The effect of cathodic bias on the electrode polarization resistance and the mechanism of oxygen reduction reaction have been studied. The passage of cathodic current leads to extensive impact to the LSM/YSZ interface microstructure and significantly enhances the electrochemical activity. LSM with different A-site non-stoichiometry also exhibit distinct activation behavior under cathodic bias. The final steady state performance of LSM electrode is determined by both of the polarization condition and the A-site non-stoichiometry. Under high current density (300mAcm-2), the stoichiometric LSM shows better performance than the A-site non-stoichiometric LSM electrodes, in contrast with the fact that it has the highest polarization resistance under OCV condition.