Characterization, Electrical and Electrochemical Study of La0.9Sr1.1Co1-xMoxO4(x <= 0.1) as Cathode for Solid Oxide Fuel Cells

In this study, Ruddlesden-Popper La0.9Sr1.1Co1-xMoxO4(x <= 0.1) powders were successfully synthesized using a modified sol-gel method. The structural analysis revealed that all samples had a tetragonal phase at room temperature. The electrical conductivity measurements showed that all samples had semiconducting behavior in the range of room temperature to 850 degrees C. Moreover, it was found that the electrical conductivity of the ceramics was enhanced with the increase of Mo doping, at temperatures higher than 300 degrees C up to 850 degrees C. This enhancement of the electrical conductivity can be due to Co3+-O-Mo5+-O-Co(2+)double-exchange interaction. The EIS measurements of the symmetrical cells were carried out forx = 0, 0.03 and 0.1 samples at 650 degrees C, 750 degrees C and 850 degrees C. The obtained area specific resistance (ASR) values of La(0.9)Sr(1.1)Co(1-x)Mo(x)O(4)on ceria-gadolinium oxide (CGO) electrolyte at 850 degrees C were 0.36 ohm cm(2), 0.35 ohm cm(2)and 1 ohm cm(2)for samplesx = 0, 0.03 and 0.1, respectively. These results indicate that the electrical conductivity of pure sample (La0.9Sr1.1CoO4) has been enhanced by Mo substitution in Co ion sites, but limits the oxygen ion transport.