Ultrafine, Dual-Phase, Cation-Deficient PrBa_0.8Ca_0.2Co₂O_5+δ Air Electrode for Efficient Solid Oxide Cells

Nanostructured air electrodes play a crucial role in improving the electrocatalytic activity of oxygen reduction and evolution reactions in solid oxide cells (SOCs). Herein, we report the fabrication of a nanostructured BaCoO₃-decorated cation-deficient PrBa_0.8Ca_0.2Co₂O_5+δ (PBCC) air electrode via a combined modification and direct assembly approach. The modification approach endows the dual-phase air electrode with a large surface area and abundant oxygen vacancies. An intimate air electrode-electrolyte interface is in situ constructed with the formation of a catalytically active Co₃O₄ bridging layer via electrochemical polarization. The corresponding single cell exhibits a peak power density of 2.08 W cm^-2, an electrolysis current density of 1.36 A cm^-2 at 1.3 V, and a good operating stability at 750 °C for 100 h. This study provides insights into the rational design and facile utilization of an active and stable nanostructured air electrode of SOCs.