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 degrees 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-delta (LSCF) and a recently developed electrode material, SrTi0.3Fe0.55Co0.15O3-delta (STFC), with addition of PrOx nanoparticles. Single-step PrOx infiltration improves performance of both LSCF and STFC across all tested temperatures (450-650 degrees 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 Omega cm(2) at 550 degrees C increasing over similar to 800 h before stabilizing at 0.27 Omega cm(2). This represents a factor of similar to 10 resistance decrease compared to the LSCF electrode at 550 degrees C. A distribution of relaxation times analysis sheds light on the electrochemical mechanisms impacted by PrOx. (C) 2019 Elsevier Ltd. All rights reserved.