High temperature properties of Sr2MgMo0.9TM0.1O6−δ (TM = Mn, Co and Ni)

Abstract

High temperature properties of Sr2MgMo0.9TM0.1O6−δ (SMMTM; TM = Mn, Co and Ni) and Sr2MgMo2O6 (SMMO) compounds were studied for evaluating SMMTM materials as SOFC electrodes. SMMTM and SMMO compounds were synthesised by the combustion method, followed by annealing in air at temperatures between 1000 and 1200 °C. Rietveld structural analysis of XRD patterns showed that the TM-dopants substitute Mo cations with a solubility limit of 10% of Mo. SMMTM compounds are thermodynamically stable in 10%H2-Ar until 900 °C. Electrical conductivities of SMMTM under reducing atmosphere were three orders of magnitude higher than in air. Although the partial replacement of Mo by Mn or Ni in Sr2MgMoO6−δ decreases the electrical conductivity in both atmospheres, an increase of conductivity in 10%H2 atmosphere was observed for SMMCo compound. Whilst the area specific resistance (ASR) are not significantly affected by Mo-substitution in reducing atmospheres, the ASR of SMMTM materials as cathodes are improved.