Application of ( Sm0.5Sr0.5 ) CoO3 as a Cathode Material to ( Zr , Sc ) O2 Electrolyte with Ceria-Based Interlayers for Reduced-Temperature Operation SOFCs

Application of (Sm 0.5 Sr 0.5 )CoO 3 as a cathode material on Zr 0.89 Sc 0.1 Ce 0.01 O 1.95 electrolyte for reduced-temperature operation solid oxide fuel cells (SOFCs) was investigated in detail. As a protective layer for preventing the unfavorable solid-state reactions between materials, doped ceria thin films with an apparent density range between 50 and 80% were fabricated on the electrolyte by a cost-effective wet ceramic process using nanometer (Ce 0.8 Sm 0.2 )O 1.9 and submicrometer (Ce 0.9 Gd 0.1 )O 1.95 powders. The impact of doped ceria interlayers on the performance of (Sm 0.5 Sr 0.5 )CoO 3 cathode was investigated by X-ray diffraction and ac impedance measurements. It was found that controlling the microstructure of interlayers is important for (Sm 0.5 Sr 0.5 )CoO 3 cathodic performance. The (Sm 0.5 Sr 0.5 )CoO 3 cathode deposited on Zr 0.89 Sc 0.1 Ce 0.01 O 1.95 electrolyte coated by (Ce 0.8 Sm 0.2 )O 1.9 or (Ce 0.9 Gd 0.1 )O 1.95 interlayer can reach an interface conductivity of 4.4 or 7.2 S/cm 2 , respectively, at 700°C.