High-performance Gd0.2Ce0.8O2-impregnated LaNi0.6Fe0.4O3−δ cathodes for intermediate temperature solid oxide fuel cell

High-performance LaNi0.6Fe0.4O3−δ (LNF) cathode for intermediate temperature solid oxide fuel cell is fabricated by the ion impregnation of oxygen ion conducting Gd-doped ceria (GDC, Gd0.2Ce0.8O2). The microstructure of the GDC-impregnated LNF cathode is characterized by the dispersion of nano-sized GDC particles in the LNF porous framework. The particle size of the impregnated GDC phase is in the range of 40–50 nm. Uniform distribution of the nano-sized ionic conducting GDC phase significantly enhances the cathode activities for the O2 reduction reaction. In the case of the 21.3 wt.% GDC-impregnated LNF cathode, the specific polarization resistance (Rp) is 0.13 Ω cm2 at 750 °C, a reduction by 81.43% compared with that of the pure LNF cathode at the same temperature. The results indicate that GDC impregnation has significant electrocatalytic effect on the O2 reduction reactions on the LNF cathodes. The improved performance of GDC-impregnated LNF cathode is attributed to the extended triple-phase boundary (TPB) and enhanced oxide ion conductivity.

► Symmetric cell LNF/ScSZ/LNF sintered at 1050 °C exhibits optimal performance. ► Impregnated GDC phase significantly enhanced the LNF cathode activities for O2 reduction reaction. ► 21.3 wt.% GDC-impregnated LNF cathode shows the lowest specific polarization resistance (Rp, 0.13 Ω cm2) at 750 °C.