Silver–praseodymium oxy-sulfate cermet: A new composite cathode for intermediate temperature solid oxide fuel cells

•A novel Ag–Pr2O2SO4 composite cathode was developed.•High oxygen storage capacity facilitated gaseous oxygen to be adsorbed.•A highly active property towards oxygen reduction reactions was achieved.•The highest power density reached 1.5 W/cm2 at 800 °C.•High stability of the cell at 800 °C under load was maintained for 24 days.

Ag–Pr2O2SO4 is identified as a promising new composite material to enhance the cathodic oxygen reduction reaction in solid oxide fuel cells. Ag–Pr2O2SO4 was studied in terms of synthesis, stability of Pr2O2SO4 in CO2, and electrochemical behavior as a cathode. The performance of the composite cathode was assessed as a function of temperature by A.C. impedance using a symmetrical cell arrangement in oxygen. The global performance of an anode-supported fuel cell Ag–Pr2O2SO4/CGO/NiO-CGO was also assessed, the highest power density being 1.5 W cm−2 at 800 °C. A longevity test of this cell performed at 800 °C under load for 24 days demonstrated high stability with Ag–Pr2O2SO4 cathode.