La0.99Co0.4Ni0.6O3-δ-Ce0.8Gd0.2O1.95 as composite cathode for solid oxide fuel cells

We have studied a new composite SOFC cathode consisting of LaCo0.4Ni0.6O3-delta (LCN60) and Ce0.9Gd0.1O1.95 (CGO). The polarisation resistance (R-p) at 750 degrees C and OCV was measured to 0.05 +/- 0.01 Omega cm(2) and the activation energy was determined to be about 1 eV. The impedance spectra were modelled with an EQC model consisting of a high frequency Z(RQ) circuit and a medium frequency Gerischer impedance, Z(G). The resistance of Z(G) was found to decrease with approximately a factor of two as a consequence of infiltration of (La0.6Sr0.4)(0.99)CoO3 into the porous LCN60-CGO structure. R-p of both infiltrated and non-infiltrated LCN60-CGO cathodes is substantially lower than that of LSM-YSZ and comparable with single phase LSC cathodes at low T due to its low E-A. R-p was also found to be stable at 750 degrees C and OCV. The cathodes were integrated onto ScYSZ based anode supported cells which were measured to have an ASR of 0.16-0.18 Omega cm(2) at 750 degrees C. (C) 2010 Elsevier B.V. All rights reserved.