Effects of using (La0.8Sr0.2)0.95Fe0.6Mn0.3Co0.1O3 (LSFMC), LaNi0.6Fe0.4O3−δ (LNF) and LaNi0.6Co0.4O3−δ (LNC) as contact materials on solid oxide fuel cells

Abstract

Three lanthanum-based perovskite ceramic compounds were studied as contact materials, (La0.8Sr0.2)0.95Fe0.6Mn0.3Co0.1O3 (LSFMC), LaNi0.6Fe0.4O3−δ (LNF) and LaNi0.6Co0.4O3−δ (LNC), between a Crofer22APU interconnect and a La0.6Sr0.4FeO3 (LSF) cathode. The layers were deposited using in all cases wet colloidal spray technique. Phase structures of materials were checked by X-ray Diffraction (XRD) measurements. Electrical conductivity and thermal expansion coefficient (TEC) for these selected compounds were also determined.The important properties of the resulting {interconnect/contact layer/cathode} systems; including area specific resistance (ASR), reactivity, and adhesion of contact materials to the interconnect and to the cathode were investigated. Moreover, the electrical resistance and reactivity of the system without a contact layer, {steel/LSF/LSF} system, was measured for comparison. The contact resistance is strongly influenced by the conductivity of selected contact materials, showing the lowest ASR values for {Crofer22APU/LNC/LSF} assembly. The point microanalysis on cross-section of the systems, after ASR measurements, reveals that there is chromium enrichment in the contact and cathode layers which allows the formation of phases like SrCrO4 and Cr-containing perovskite in short exposure times. An adequate integrity and low reactivity is achieved when LNF contact coating is applied between Crofer22APU and LSF cathode without compromising the contact resistance of the system.