Abstract: Aseries of composite cathodes with various YSZadditions were investigated by ACimpedance, polarization and conductivity measurement. The electrochemical performance of the cathodes was improved by increasing the YSZaddition, and the optimal YSZaddition for the lowest electrode resistance(1.18 Ω/cm²) was found to be 40%. The rate determining step of the cathode reaction varied when YSZwas added into the LSMelectrode. The contact resistance increased as YSZaddition increased. By applying a layer of platinum on the cathode as a current collecting layer, the contact resistance decreased significantly, and the electrode resistance at₁223 K_dropped remarkably from 1.18 Ω/cm² to 0.41 Ω/cm².

Key words: Solid oxide fuel cell, Composite La(MnO₄)₃ cathode, YSZ electrolyte