Evaluation of Using LaNi0.6Fe0.4O3- Contact Layer Between La0.6Sr0.4FeO3 Cathode and Crofer22APU Interconnect for Solid Oxide Fuel Cells

摘要

Interconnect-cathode interfacial adhesion is important for the durability of solid oxide fuel cell (SOFC). Thus, the use of a conductive contact layer between interconnect and cathode could reduce the cell area specific resistance (ASR). The use of La0.6Sr0.4FeO3 (LSF) cathode, LaNi0.6Fe0.4O3- (LNF) contact layer and Crofer22APU interconnect was proposed as an alternative cathode side. LNF-LSF powder mixtures were heated at 800 degrees C for 1,000 h and at 1,050 degrees C for 2 h and analyzed by X-Ray power diffraction (XRD). The results indicated a low reactivity between the materials. The degradation occurring between the components of the half-cell (LSF/LNF/Crofer22APU) was studied. XRD results indicated the formation of secondary phases, mainly: SrCrO4, A(B, Cr)O-3 (A = La, Sr; B = Ni, Fe) and SrFe12O19. Scanning electron microscopy with energy dispersive X-Ray spectroscopy (SEM-EDX) and the X-Ray photoelectron spectroscopy (XPS) analyzes confirmed the interaction between LSF/LNF and the metallic interconnect due to the Cr vaporization/migration. An increment of the resistance of approximate to 0.007cm(2) in 1,000h is observed for (LSF/LNF/Crofer22APU) sample. However, the ASR values of the cell without contact coating, (LSF/Crofer22APU), were higher (0.31(1)cm(2)) than those of the system with LNF coated interconnect (0.054(7)cm(2)), which makes the proposed materials combination interesting for SOFC.