Performance of YBa2Cu3O7-delta-La0.6Sr0.4Co0.2Fe0.8O3-delta composite cathode for intermediate-temperature solid oxide fuel cells

摘要

In this work, different contents of La0.6Sr0.4Co0.2Fe0.8O3-delta (10, 20, 30 and 40 wt% LSCF) are added into YBa2Cu3O7-delta (YBC) to investigate its effect on the performance of solid oxide fuel cell cathode. The result shows that with addition of 30 wt% LSCF, the polarization resistance is decreased from 0.137 to 0.044 omega cm2, and the output of the single cell is increased about 50% at 800 degrees C. O2 temperature-programmed desorption and electrical conductivity test show that the oxygen exchange capacity and conductivity of YBC-LSCF are greatly improved from 600 to 800 degrees C. The equivalent circuit fitting results of electrochemical impedance spectroscopy curves under the different oxygen partial pressures of 0.05, 0.1, 0.21 and 1 atm indicate that the resistance associated with charge transfer and gas transport in the composite cathode are about 80% and 60 & ndash;80% decreased, respectively. It is found that the low conductivity and poor oxygen adsorption behavior may be the two obstacles for using YBC as a cathode material. It also can be seen that by taking the advantages of LSCF, the drawbacks of YBC are largely remedied and the synergistic effect is achieved.