Zr and Zn doped SFM materials for SOFC applications

Possessing high versatility, excellent stability over a wide range of oxygen partial pressures, and high catalytic activity, the perovskites from the Sr(Fe1−xMox)O3−d (SFM) group have attracted a lot of attention, particularly with respect to the technology of conventional solid oxide fuel cells (SOFCs) and symmetrical solid oxide fuel cells (S-SOFCs). However, their performance, especially as air electrodes, is still lacking compared to those of more specialized, dedicated cathodes. In this work, co-doping of the conventional SrFe0.75Mo0.25O3−d material with Zn and Zr is proposed to improve its catalytic capabilities through increased lattice basicity and oxygen nonstoichiometry. The impact of dopants is studied for the Sr(Fe0.75Mo0.25)1−2xZnxZrxO3−d (x # 0.2) series under both oxidizing and reducing atmospheres, including the evolution of the structure, oxygen non-stoichiometry, and transport properties. Evaluation of cathodic polarization resistance Rp shows that the selected SrFe0.6Mo0.2Zn0.1Zr0.1O3−d aterial is characterized by superior cathodic performance compared to SFM, with an Rp value of 0.15 U cm2 at ca. 740 °C and a power density of a full cell equal to 978 mW cm−2 at 900 °C. This performance, excellent for a Co-free material, makes Sr(Fe0.75Mo0.25)1−2xZnxZrxO3−d extremely promising candidate materials for
SOFC/S-SOFC technology.