Highly efficient perovskite-based fuel electrodes for solid oxide electrochemical cells via in-situ nanoparticle exsolution and electron conduction enhancement

Developing efficient fuel catalysts exhibiting high electrocatalytic activity and stability is crucial to improving the performance of solid oxide fuel/electrolysis cells for electrochemical energy storage and conversion. The oxide catalysts have been extensively investigated for replacing conventional Ni-based fuel electrodes, owing to their excellent stability and high resistance to coking in the presence of carbon-based fuels, such as during CO2 electrolysis. In this study, we propose a novel strategy to enhance the oxide electrocatalyst performance via nanoparticle exsolution and electron conduction improvement. In this strategy, the A-site deficient Sr0.95Ti0.3(Fe0.9Ru0.1)(0.7)O3-delta (STFR) was coupled with Sr2Fe1.5Mo0.5O6-delta (SFM) to yield a composite electrode. STFR with in-situ exsolved Fe-Ru nanoparticles provided high catalytically active sites, whereas SFM increased the electron conduction pathways, further boosting the electrode activity. When the composited electrodes were applied to an LSGM electrolyte-supported cell, the Fe-Ru exsolved STFR-SFM exhibited superior activity, surpassing those of previously reported performance metrics, including >1.5 W cm(-2) peak power density in fuel cell mode, >1.75 A cm(-2) (at 1.3 V) in the steam electrolysis mode, and >2.15 A cm(-2) (at 1.3 V) in direct CO2 electrolysis mode at 800 degrees C. The composite electrode demonstrates excellent electrochemical catalytic activity, remarkable durability, and preferential selectivity toward CO2 electrolysis.