Structural properties and electrical conductivity of perovskite-type oxides in SOFCs

Abstract

Structural properties and electrical conductivity of Sr2MgMoO6 (SMMO) and Sr2MgMo0.9TM0.1O6-δ (TM = Co, Mn) compounds were analyzed for establishing the usefulness of these materials as Solid oxide fuel cells (SOFC) anode. SMMO and SMMTM were synthesized through combustion-solution method and annealing in air at temperatures between 1000 and 1200 °C. SMMO and SMMCo with triclinic structures, and SMMMn with tetragonal structure at room temperature showed a cubic symmetry at 800 °C, which are apparently coking-resistant. Mn-doping in SMMO is detrimental for electrical conductivity in diluted-H2 environment, whilst the highest conductivity value was recorded for Co-containing sample on Mo-site of SMMO double perovskite. On the other hand, the oxygen reduction reaction of Pr2-xNdxNiO4+δ, (x=0, 0.3, 1 and 1.7) SOFC cathodes deposited on La0.9Sr0.1Ga0.8Mg0.2O2.85 electrolyte was studied by electrochemical impedance spectroscopy. The obtained results showed that the chemical reactivity between Pr2-xNdxNiO4+δ oxides with electrolyte materials is a serious drawback in their use as cathode in SOFC.