Mechanisms of PrO x Performance Enhancement of Oxygen Electrodes for Low Temperature Solid Oxide Cells

Abstract

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 La_0.6Sr_0.40.2Fe_0.8O_3-δ (LSCF) and a recently developed electrode material, SrTi_0.3Fe_0.55Co_0.15O_3-δ (STFC), with addition of PrO_x nanoparticles. Single-step PrOx infiltration improves performance of both LSCF and STFC across all tested temperatures (450 to 650 °C) with the most significant enhancements at lower temperatures. STFC modified with PrO_x yields the best overall performance and stability, with the initial polarization resistance of 0.20 Ω·cm² at 550 °C increasing over ~ 800 hours 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 timesanalysis sheds light on the electrochemical mechanisms impacted by PrO_x.