SrMo_(1-x)FexO_(3-δ) perovskites anodes for performance solid-oxide fuel cells

摘要

Oxides of composition SrMo_(1-x)Fe_xO_(3-δ) (x= 0.1, 0.2) have been prepared, characterized and tested as anode materials in single solid-oxide fuel cells, yielding output powers close to 900 mWcm~(-2) at 850°C with pure H2 as a fuel. This excellent performance is accounted for the results of an "in-situ" neutron powder diffraction experiment, at the working temperature of the SOFC, showing the presence of a sufficiently high oxygen deficiency, with large displacement factors for oxygen atoms that suggest a large lability and mobility, combined with a huge metal-like electronic conductivity, as high as 340 S·cm~(-1) at T= 50°C for x= 0.1. The magnitude of the electronic conductivity decreases with increasing Fe- doping content. An adequate thermal expansion coefficient, reversibility upon cycling in oxidizing-reducing atmospheres and chemical compatibility with the electrolyte make these oxides good candidates for anodes in intermediate-temperature SOFC (IT-SOFCs).