Effect of Nanocrystalline Perovskite-based Cathode Compositions on SOFC Performance: An Aspect of Cell Stability with Composite Interlayer

摘要

Multicomponent nanocrystalline Sr-doped lanthanum manganite (La_(0.65)Sr_(0.3)MnO_3, LSM) and a composite cathode comprising of Sr-doped lanthanum ferrite (La_(0.54)Sr_(0.4)Co_(0.2)Fe_(0.8)O_3, LS-1) and cobaltite (La_(0.54)Sr_(0.4)Fe_(0.2)Co_(0.8)O_3, LS-2) were synthesized. Powder was characterized thoroughly. Sintering characteristics of all the cathode compositions were correlated with densification of the bulk cathode material and the electrical characterization of the sintered cathode compositions showed that the composite cathode exhibits higher electrical conductivity compared to LSM. Another composite (L80-C20) material has been synthesized to be used as a part of the intermediate bilayer containing 80% (50%LS-1+50%LS-2) cathode composite and 20% Co-doped CGO. Symmetric cell study showed the electrode polarization of this composite as low as 0.012 Ω-cm~2. Systematic stability studies of the electrochemical performance using single cells with different configurations revealed that use of intermediate bi-layer, one layer of CoCGO and another interlayer containing L80-C20 increases the cell stability in conjunction with doped lanthanum ferrite and cobaltite based composite electrodes.