Characterization of Novel Perovskite-Type La_0.6Sr_0.2Ca_0.2Co_1-YFe_YO_3-δ Cathode Materials Prepared by Solid State Reaction for IT-SOFCs

Abstract:

Perovskite-type cathode materials La_0.6Sr_0.2Ca_0.2Co_1-yFe_yO_3-δ (0.2≤y≤0.5, marked as LSCCF62282, LSCCF62273, LSCCF62264 and LSCCF62255) for intermediate-temperature solid oxide fuel cells (IT-SOFCs) were prepared by solid state reaction. The establishment process and phase transformation were measured by TG-DTA, FT/IR and XRD techniques. Single hexagonal perovskite phase can be achieved after sintered at 1100 °C for 3 h. Mixed conductivity, thermal expansion behavior and chemical stability of sintered samples at 1100 °C for 3 h have been investigated. At intermediate temperature (600-800 °C), the mixed conductivity characterized by DC four-probe technique is higher than 100 S/cm. LSCCF62282 has the highest conductivity of 297.3 S/cm at 700 °C among the four samples. At lower temperatures, the conductivity follows small polaron hopping mechanism. Thermal expansion coefficients (TECs) of the samples from 50 °C to 850 °C exhibit a reducing tendency with increasing amount of doped Fe³⁺. Thermal expansion behavior can be improved by doping with Ca²⁺ and Fe³⁺ commonly. XRD pattern for LSCCF62282 and YSZ mixture sintered at 800 °C for 6h indicates that cathode material LSCCF62282 is chemically stable against YSZ electrolyte at operating temperature.

• Periodical: Applied Mechanics and Materials (Volumes 130-134)
• Pages: 1058-1061
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.130-134.1058
• Online since: October 2011
• Authors: Chen Li, Jie Zhao, Ling Long Kong, Yong Chang Ma
• Keywords: Chemical Stability, Mixed Conductivity, Perovskite-Type Cathode Materials, Solid-State Reaction, Thermal Expansion Behavior

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