Smart utilization of in-situ exsolution occurring in Ag doped PrBa0.5Sr0.5Co2O5+δ nanofiber air electrode of intermediate temperature reversible solid oxide cells

Abstract

Low-temperature operation of reversible solid oxide cells can effectively improve their stable and economical application. However, insufficient catalytic activity of the air electrode is the limiting factor for reversible solid oxide cells. Here, we fabricate a novel Pr0.9Ag0.1Ba0.5Sr0.5Co2O5+δ nanofibers with enhanced electrocatalytic activities via an electrospinning technique and in-situ exsolution. The study confirms the advantage of morphology engineering in enlarging the catalytic interface and reactive sites, and the cells with Pr0.9Ag0.1Ba0.5Sr0.5Co2O5+δ nanofibers air electrode exhibit obviously decreased polarization resistance (0.06 Ω cm2), increased electrolysis current density of 0.65 A cm-2 (50 vol% absolute humidity and 1.5 V), and adequate power density (~ 0.5 W cm-2) at 700 °C. Also, the cell exhibits exceptional reversibility and stability during the long-term test. The enhancement may be assigned to the in-situ exsolution of Ag nanoparticles at Pr0.9Ag0.1Ba0.5Sr0.5Co2O5+δ surface and better interface combination between the air electrode and electrolyte. This work provides an exemplificative study on the favorable nanofibers air electrode for high performance intermediate temperature reversible solid oxide cells.