Design, synthesis and performance of Ba-doped derivatives of SrMo0.9Fe0.1O3-δ perovskite as anode materials in SOFCs

The oxides SrMo1-xFexO3-delta (x = 0.1 and 0.2) have recently been described as excellent anode materials for solid-oxide fuel cells at intermediate temperatures (IT-SOFC) with LSGM as the electrolyte. In this work we have partially replaced Sr by Ba in a compound of formula Sr0.9Ba0.1Mo0.9Fe0.1O3-delta, in order to expand the unit-cell size and thereby improve the ionic diffusion of O-2(-) ions through the crystal lattice. The anode materials must be stable under reducing conditions, since they work in the presence of the fuel (H-2) at elevated temperatures. These anodes are inspired in the SrMoO3 perovskite, which contains Mo4+ ions, stable in very reducing conditions. This novel oxide has been structurally characterized from x-ray (XRD) and neutron powder diffraction (NPD) data; the structure is defined at room temperature in the Pm-3m space group, and shows oxygen vacancies, necessary for the performance of this material as mixed ionic-electronic (MIEC) oxide. In single test cells supported on LSGM, the materials generated output powers close to 500 mW/cm(2) at 850 degrees C using pure H-2 as fuel. The thermal expansion is linear, with TEC = 10.93 X 10(-6) K-1. The chemical compatibility with the LSGM electrolyte was also verified. (C) 2018 The Chinese Ceramic Society. Production and hosting by Elsevier B.V.