Flexible Cu1.5Mn1.5O4 combined with Co3O4 and Al2O3 conductive ceramic film as a cathode current collecting layer for solid oxide fuel cells

Abstract

Novel flexible conductive ceramic films consisting of Cu1.5Mn1.5O4, Co3O4 and Al2O3 are developed for the cathode current collecting layer (CCCL) in solid oxide fuel cell (SOFC) stacks. These ceramic films are prepared by a water-based tape-casting method and sintered in situ at the operation temperature of intermediate temperature (IT)-SOFCs. The effects of addition amounts of Co3O4 and Al2O3 on the electrical conductivity of the CCCL and area specific resistance (ASR) of (La0.75Sr0.25)0.95MnO3-δ (LSM) cathode/the CCCL/SUS430 interconnect sandwich are studied. The results indicate that adding 3 wt.% of Co3O4 as sintering aids in Cu1.5Mn1.5O4 precursor powder can promote its sintering and thus reduce its contact resistance with neighboring components. Further combining Al2O3 as the binder with Cu1.5Mn1.5O4-3 wt.% Co3O4, though electrical conductivity of obtained materials decreases with the amount of Al2O3 addition increasing, the minimum ASR of 24.4 mΩ cm2 at 800 °C and a stable ASR of around 27 mΩ cm2 at 750 °C are achieved on LSM cathode/Cu1.5Mn1.5O4-3 wt.% Co3O4-10 wt.% Al2O3 CCCL/SUS430 interconnect sandwich. The developed flexible CCCL shows pronounced low contact resistance and high stability. Moreover, it can be easily cut and sintered in situ in SOFC stack, which is promising for the practical application in SOFC stacks.