Exceptional cathodic performance of nanostructured La–Sr–Co–Fe–O highly dispersed in porous yttria-stabilized zirconia frameworks for intermediate-temperature solid oxide fuel cells

Improving the cathode performance of intermediate-temperature solid oxide fuel cells (SOFCs) requires enhancing the oxygen reduction reaction kinetics by optimizing the interface in the composite cathode. In this study, a nanostructured La_0·6Sr_0·4Co_0·2Fe_0·8O₃ (LSCF) cathode highly dispersed within a yttria-stabilized zirconia (YSZ) scaffold has been fabricated using ultrasonic spray infiltration. To optimize the nanoparticle concentration, infiltration has been performed over 2, 6, 8 and 10 cycles, followed by low-temperature firing at 800 °C. Microstructural analysis reveals that 8 cycles of infiltration yield the most uniform distribution, forming interconnected LSCF particles necessary for electronic percolation. Excessive infiltration leads to nanoparticle aggregation and detachment from the scaffold. The electrochemical study performed on the symmetric cell exhibits an area-specific resistance of 0.047 Ω cm² at 700 °C after 8 infiltration cycles, which is better than that of the conventional screen-printed cathode. The optimized cathode has been further tested for fuel cell performance on a Ni–Fe metal-supported cell, and a peak power density of ∼0.42 W/cm² has been achieved at 700 °C. Thus, this study elucidates the potential of LSCF nanoparticle infiltration for fabricating high-performance cathodes at a low processing temperature for advancing SOFC technology.