Multi-phase heterostructure fuel electrode with exsolved metals and oxides enables efficient and robust operation in solid oxide cells

Solid oxide cells (SOCs) are attractive due to their high efficiency and dual functionality, enabling electricity generation and electrochemical energy conversion. However, the widespread adoption of SOCs is limited by the inherently low catalytic activity and insufficient durability of traditional electrode materials. Herein, the multiphase heterogeneous electrode Pr₂O₃@BiFe@Pr_1-xBi_xFeO_3-δ, in which Bi, Fe metals, and Pr₂O₃ are exsolved in-situ, was fabricated under reducing conditions. The CO₂ adsorption capacity is enhanced by adjusting the interfacial acidity via Pr₂O₃, and the in situ-anchored metal nanoparticles (Bi and Fe) at the interface enable efficient charge transfer and CO desorption. Electrochemical investigations reveal that the electrolyte-supported single cell employing x = 0.2 as the fuel electrode achieves a peak power density of 0.63 W cm⁻² and an electrolysis current density of −1.07 A cm⁻² (1.5 V) at 850 °C. More significantly, the electrolytic current density of the cell remains almost constant during the durability test and exhibits stability during sustained electrolysis. The findings of this study offer new design and research perspectives for enhancing the activity and durability of fuel electrode catalysts in SOCs.