Mechanisms of PrOx performance enhancement of oxygen electrodes for low and intermediate temperature solid oxide fuel cells

Recent developments in solid oxide cells focus on decreasing operating temperatures below 600 °C for improved cost and electrochemical stability in order to improve viability for commercialization. In this work, we improve the performance and stability of La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF) and a recently developed electrode material, SrTi0.3Fe0.55Co0.15O3−δ (STFC), with addition of PrOx nanoparticles. Single-step PrOx infiltration improves performance of both LSCF and STFC across all tested temperatures (450–650 °C) with the most significant enhancements at lower temperatures. STFC modified with PrOx yields the best overall performance and stability, with the initial polarization resistance of 0.20 Ω cm2 at 550 °C increasing over ~800 h before stabilizing at 0.27 Ω cm2. This represents a factor of ~10 resistance decrease compared to the LSCF electrode at 550 °C. A distribution of relaxation times analysis sheds light on the electrochemical mechanisms impacted by PrOx.