Characteristics of SrCo1 − xSnxO3 − δ cathode materials for use in solid oxide fuel cells

In this study, introduction of tin ions in the SrCoO3 − δ oxide is attempted to modify its electrochemical behavior for serving as a cathode of intermediate-temperature solid oxide fuel cells (IT-SOFCs). Doping of tin ions appears to stabilize the cubic Pm-3m phase of the SrCo1 − ySnyO3 − δ ceramics but generates SrSnO3 precipitates and inhibits the grain growth as y value rises to a level greater than 10%. Obtained at 550 °C, the maximum electrical conductivity of SrCo0.95Sn0.05O3 − δ reads 545 S cm− 1. Single cells with a structure of NiO–Sm0.2Ce0.8O2 − δ (SDC)/SDC/SrCo0.95Sn0.05O3 − δ–SDC are built and characterized. Though SrCo0.95Sn0.05O3 − δ is regarded as an MIEC (mixed ionic/electronic conductivity material), adding SDC to SrCo0.95Sn0.05O3 − δ guarantees good adhesion to and fine electrical contact with the electrolyte layer, thereby contributing to the reduction in R0 and RP values. The single cell with the SrCo0.95Sn0.05O3 − δ–SDC composite cathode at 700 °C registers respectively an R0 value of 0.044 Ω cm2 and an RP value of 0.109 Ω cm2. In the absence of microstructure optimization and hermetic sealing of cells, a high power density of 0.847 W cm− 2 is reached. SrCo1 − ySnyO3 − δ thus emerges to be a promising cathode material for IT-SOFCs applications.

► Doping of tin ions stabilizes the cubic Pm3m phase of the SrCo1 − ySnyO3 − δ ceramic.
► SrSnO3 precipitates was observed as y value rose to a level greater than 10%.
► Cell with composite cathode at 700 °C has R0 of 0.044 Ω cm2 and RP of 0.109 Ω cm2.
► An MPD of 0.847 W/cm2 was reached for cell with SrCo1 − ySnyO3 − δ cathode.
► SrCo1 − ySnyO3 − δ thus emerges to be a promising cathode material for IT-SOFCs.