Combustion synthesis and characterization of LSCF-based materials as cathode of intermediate temperature solid oxide fuel cells

✍ Scribed by Atanu Dutta; Jayanta Mukhopadhyay; R.N. Basu

• Publisher: Elsevier Science
• Year: 2009
• Tongue: English
• Weight: 856 KB
• Volume: 29
• Category: Article
• ISSN: 0955-2219
• DOI: 10.1016/j.jeurceramsoc.2008.11.011

✦ Synopsis

Nanocrystalline SOFC cathode materials of perovskite family, La 1-x Sr x M 1-y Co y O 3 , where 0 < x ≤ 0.5, 0 < y ≤ 0.8 (M is transitional metal = Mn or Fe), have been synthesized at a relatively low temperature by combustion synthesis using alanine as a novel fuel. Detailed X-ray powder diffraction analyses show 47-96% phase purity in the as-synthesized powder and upon calcination at ∼825 • C single-phase material is obtained wherein the nanocrystallinity (crystallite size ∼19-24 nm) is retained. Densification studies of the materials are carried out within 900-1100 • C. The coefficient of thermal expansion (CTE) of these cathodes is measured. Electrical conductivity of the cathodes sintered at different temperatures are measured in the temperature range 700-900 • C and correlated with the density of the sintered materials. The electrochemical performances of Ni-YSZ anode-supported SOFC having YSZ electrolyte (∼10 m) with CGO interlayer (∼15 m) are studied with the developed cathodes in the temperature range 700-800 • C using H 2 as fuel and oxygen as oxidant. Highest current density of ∼1.7 A/cm 2 is achieved during testing at 800 • C measured at 0.7 V with a cathode composition of La 0.5 Sr 0.5 Co 0.8 Fe 0.2 O 3 . Precipitation of nanocrystalline grains over the core grains in porous microstructure of this cathode might be one of the reasons for such high cell performance.