Chivite Lacaba M., Alveal A., Prado-Gonjal J., Alonso J.A., Fernández Díaz M.T., Troncoso L., Cascos V.
ACS Applied Energy Materials
Recent studies have demonstrated the possibility of stabilizing the cubic or tetragonal perovskite phases in the SrCoO3-d system at room temperature by partially replacing Co atoms with small amounts of highly charged cations like Ti4+ in SrCo0.95Ti0.05O3-d. This material gives extraordinary performances as a cathode for solid oxide fuel cells (SOFCs) at intermediate temperatures (800-850 °C). In this work, we have tried to still improve this cathode in a cleaner and low-priced material by reducing its Co content, since Co is a high-cost and toxic element, additionally reducing its thermal expansion coefficient (TEC), to make it more mechanically compatible with the rest of the components of a SOFC. SrCo0.50Fe0.45Ti0.05O3-d perovskite has been obtained by the citrate method, introducing 45% of Fe in the Co and Ti positions. Its crystalline structure has been studied by X-ray diffraction (XRD) and neutron powder diffraction (NPD) and has been correlated with mechanical and electrical properties. A chemical compatibility study between SrCo0.50Fe0.45Ti0.05O3-d and the electrolyte La0.8Sr0.2Ga0.83Mg0.17O3-d (LSGM) revealed that both materials do not interact at high temperatures. TEC measurements show a linear expansion over the entire temperature range. Finally, the perovskite showed good electrical conductivity and an encouraging power density value of 667 mW/cm2 at 850 °C, which indicate that this material is a promising cathode for SOFCs at intermediate temperatures. © 2023 American Chemical Society.
