Interconnect material chromium deficient lanthanum calcium chromites as novel cathodes for solid oxide fuel cells

• 1、Department of Materials Science and Engineering, University of Science and Technology of China

Abstract：High-performance interconnect material chromium deficient lanthanum calcium chromites La0.7Ca0.3Cr0.97O3-δ (LCC97) perovskite oxide was prepared by a modified Pechini method and examined as novel cathode materials for solid oxide fuel cells (SOFCs) based on yttria-stabilized zirconia (YSZ) and samarium doped ceria (SDC) electrolytes at intermediate temperatures (650-850 °C). Chemical compatibility, sintering character, electrical conductivity and thermal expansion were investigated to characterize the compatibilities of La0.7Ca0.3Cr0.97O3-δ (LCC97) with Y0.16Zr0.84O2-δ (YSZ) and Sm0.2Ce0.8O2-δ (SDC), respectively. The electrochemical performance of the LCC97 based composite cathode on the electrolyte of YSZ and SDC was studied by electrochemical impedance spectroscopy (EIS) for their potential utilization in the intermediate-temperature SOFCs. The XRD analysis indicates LCC97 chemically compatible with both YSZ and SDC. There was no reaction between LCC97 and YSZ/ SDC electrolytes even at a SOFC co-firing temperature (1400 °C) in air. The LCC97 sintered at 1250 °C had the conductivity of 62.0 S.cm−1 at 850 °C in air, which is about 2.6 times as high as that of La0.7Ca0.3CrO3-δ with no chromium deficiency. The TEC of the material was about 11.4×10−6 K−1, which is very compatible to that of other common used SOFC components. The interfacial polarization resistances (area specific resistances) of the LCC97-SDC (1:1) composite cathode were much lower than the LCC97-YSZ (1:1) composite cathode. At 800 °C, the ASRs of composite cathodes were only 0.15 Ω.cm2 and 0.30 Ω.cm2 for LCC97-SDC (1:1) and LCC97-YSZ (1:1), respectively.

keywords： Solid oxide fuel cell Cathode Interconnect Lanthanum chromites

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