A study of LSM-YSZ composite cathodes by AC impedance and polarization

A series of composite cathodes with various YSZ additions;were investigated by AC impedance, polarization and conductivity measurement. The electroche mical performance of the cathodes was improved by increasing the YSZ additi on, and the optimal YSZ addition for the lowest electrode resistance (1.18 Omega/ cm(2)) was found to be 40%. The rate-determining step of the cathode reaction varied when YSZ was added into the LSM electrode. The contact res istance increased as YSZ addition increased. By applying a layer of platinu m on the cathode as a current collecting layer, the contact resistance decr eased significantly , and the electrode resistance at 1223 K dropped remark ably from 1.18 Omega /cm(2) to 0.41 Omega /cm(2).