Enhancing oxygen storage capacitance of La-doped ceria barrier layer via transition metal sintering additives (Mn, Co, Cu) for empowering SOFC performance at high-current condition

Abstract

Achieving a highly dense ceria-based diffusion barrier layer in a layered SOFC configuration typically requires a high sintering temperature to effectively block impurities from migrating from the electrode into the electrolyte. However, such high temperatures often result in undesirable elemental diffusion between the doped ceria barrier layers and the electrolyte, in addition to significantly increasing manufacturing costs. Lowering the sintering temperature can mitigate these issues by reducing Ce-ZrO2 solid solution formation at the interlayer/electrolyte interface, while also offering a more cost-effective approach. Preventing secondary phase formation within SOFCs is crucial for enhancing cell performance and durability, representing a key step towards their commercialization. In this study, we investigated various transition metals (Mn, Co, and Cu) as effective additives to not only lower the sintering temperature but also enhance the oxygen storage capacitance of the La-doped ceria (Ce0.6La0.4O2-delta-LDC) barrier layer on a thin YSZ electrolyte. The LDC-1 wt% Mn shows excellent electrochemical performance of similar to 2.05 W cm(-2) at 800 degrees C. Furthermore, Mn-added LDC, which was successfully sintered at lower temperatures, exhibited a notably higher increase in chemical capacitance compared to the other additives under SOFC operating conditions with a high current density range.