Enhanced oxygen electrode kinetics at low temperatures: an infiltrated Sr(Ti0.3Fe0.55Co0.15)O3-δ-La0.8Sr0.2Ga0.8Mg0.2O3-δ nanocomposite for solid oxide cells

Low-temperature (<= 650 degrees C) solid oxide cells hold great potential for next-generation fuel cells and electrolyzers. Although Sr- and Mg-doped LaGaO3 (LSGM) is a promising electrolyte for this purpose, developing an electrode that meets all the performance, stability, and compatibility criteria remains challenging. Herein, we report a high-performance nanocomposite oxygen electrode fabricated by infiltrating a porous LSGM framework with the Sr(Ti0.3Fe0.55Co0.15)O3-delta (STFC) catalyst, noted for its excellent oxygen transport properties and surface stability. This novel STFC-LSGM electrode, composed of similar to 80.1 vol% LSGM and similar to 4.2 vol% STFC, exhibits an exceptionally low polarization resistance of similar to 0.06 Omega cm2 at 600 degrees C, with a degradation of similar to 11.2% per 1000 h under open-circuit conditions. The mechanisms behind this remarkable performance and stability are investigated via impedance analysis using a microstructure-coupled transmission-line model. Integrated into a full cell with a thin LSGM electrolyte and a Sr0.8La0.2TiO3-delta support, the optimized electrode delivers impressive performance, achieving a fuel cell power density of similar to 1.54 W cm-2 and a steam electrolysis current density at 1.3 V of similar to 1.37 A cm-2, both at 600 degrees C. This work demonstrates a promising route for developing high-performance oxygen electrodes for LSGM-based SOC applications.