Promoted electrochemical performance of intermediate temperature solid oxide fuel cells with Pd0.95Mn0.05O-infiltrated (La0.8Sr0.2)0.95MnO3−δ–Y0.16Zr0.84O2 composite cathodes

• Pd0.95Mn0.05O-infiltrated LSM-YSZ cathode was applied in large size SOFC.
• Electrochemical performance of infiltrated cell was significantly improved.
• Thermal cyclicability and long-term stability was evaluated at 750 °C.
• The relativity between particle growth and performance degradation was discussed.

Pd0.95Mn0.05O-infiltrated (La0.8Sr0.2)0.95MnO3−δ–8 mol.% Y2O3 stabilized ZrO2 (LSM-YSZ) cathode is used to large size (11 × 11 × 0.1 cm) Ni-YSZ anode-supported planar cells for the first time and electrochemically evaluated in the intermediate temperature range from 650 to 800 °C with H2 as the fuel and air as the oxidant. The initial open circuit voltage (OCV) of the cell is 1.15 V, and the achieved maximum power density increases from 328 to 734 mW cm−2 with the increase of testing temperatures from 600 to 800 °C, which is almost 2.6 times higher than that of the cell with conventional LSM-YSZ cathode. After each thermal cycle between 750 and 300 °C, the OCV remains almost unchanged and the cell voltage decreases less than 0.007 V, indicating that the cell is capable of thermal cycling. The cell voltage at 310 mA cm−2 and 750 °C declines linearly with testing time at a rate of 2.6 × 10−4 V h−1 for the growth of the infiltrated Pd0.95Mn0.05O size, resulting in reduction of the total surface area of the particles. The mechanism of performance degradation of the cell with Pd0.95Mn0.05O-infiltrated LSM-YSZ composites cathode is discussed in detail.