Performance and Activation of La_(0.8)SrO2MnO_(3-δ) Thin-Film Cathodes^

摘要

La_(0.8)Sr_(0.2)MnO_(3-δ) (LSM) is one of the most commonly utilized cathodes for SOFC systems. Although well studied, a number of questions relating to the electrochemical performance of LSM-based electrodes remain unanswered. For example, it has been observed that the performance of LSM-based electrodes improves dramatically upon the first application of current. This activation behavior has been attributed to a number of mechanisms including restructuring or reduction of the LSM phase or surface segregation of Sr. In addition, it is suggested that the reaction mechanism for LSM-based electrodes changes as polarization increases. That is, a bulk pathway for oxygen ion transport in LSM becomes available under cathodic polarization due to reduction of the LSM.^