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−δ (LCN60) and Ce0.9Gd0.1O1.95 (CGO). The polarisation resistance (RP) at 750 °C and OCV was measured to 0.05 ± 0.01 Ω cm2 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 ZRQ circuit and a medium frequency Gerischer impedance, ZG. The resistance of ZG was found to decrease with approximately a factor of two as a consequence of infiltration of (La0.6Sr0.4)0.99CoO3 into the porous LCN60–CGO structure. RP 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 EA. RP was also found to be stable at 750 °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 Ω cm2 at 750 °C.