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Regular version of the site

Article

Evaluation of La2CoTi0.7Mg0.3O6 as an electrode material for a symmetrical SOFC

Journal of Electroceramics. 2018. Vol. 40. No. 2. P. 162-169.
Mazo G., Lyskov N., Istomin S., Antipov E.

La2CoTi0.7Mg0.3O6 (LCTM) material has been prepared at 1473K for 24 h in the air. X-ray powder diffraction study has revealed that it contains two orthorhombic perovskite phases (in a ratio 1:4) with close unit cell parameters. Annealing of LCTM in reducing (Ar/H2, 8%) atmosphere at 1173K for 12h has resulted in the preparation of a single-phase material containing the GdFeO3-type perovskite phase with the unit cell parameters of a=5.5631(3) Å, b=5.5462(3) Å, c=7.8522(5) Å. LCTM material exhibits a reversible transformation of a mixture of two perovskite phases with close cation content in the air and a single perovskite phase in a reducing atmosphere. Both as-prepared and reduced LCTM samples have been studied by thermogravimetric analysis and dilatometry in the air and Ar/H2 (8%). No chemical interaction between the as-prepared LCTM and standard electrolyte materials for SOFC like GDC and YSZ has been observed up to 1273K. High-temperature electrical conductivity of the as-prepared LCTM at variable oxygen partial pressure (10-4-0.21 atm) showed weak dependence over pO2 with Ea=0.48±0.01 eV. AC impedance study of the symmetrical cells LCTM/GDC/LCTM have revealed ASR value at 1173K of ~8.1±0.1 Ω∙cm2 in air and 0.24±0.05 Ω∙cm2 in a reducing atmosphere. These results allow to consider LCTM as a promising electrode material for a symmetrical SOFC