PdO/ZrO2 engineered (La0.8Sr0.2)0.95MnO3-δ-(Y2O3)0.08(ZrO2)0.92 cathode for use in intermediate temperature solid oxide fuel cells

Abstract

To enhance the electrochemical performance of (La0.8Sr0.2)0.95MnO3-δ-8 mol. % Y2O3 stabilized ZrO2 (LSM-YSZ) cathode at reduced temperatures, PdO and ZrO2 (Pd/Zr = 0.8/0.2) are co-infiltrated into the LSM-YSZ scaffold. Such prepared composite cathode is investigated at temperatures between 600 and 750 °C and cathodic current densities of 400 and 800 mA cm−2. It is observed that PdO particles are uniformly deposited on the surface of the LSM-YSZ and surrounded by nano-sized ZrO2 particles. This distinctive microstructure possesses improved thermal stability under current at 750 °C due to the hindering effect of ZrO2 on the agglomeration and growth of PdO particles. As a result, the electrocatalytic activity of the cathode for oxygen reduction reaction (ORR) is greatly enhanced due to presence of the self-limited PdO particles. At open circuit voltage, the initial polarization resistance decreases from 1.68 to 0.40 Ω cm2 as temperature increases from 600 to 750 °C; and the polarization resistance is fully stabilized at the level of 0.36 and 0.34 Ω cm2, respectively, after current polarization at 750 °C under 400 and 800 mA cm−2 for less than 200 h.