An innovative efficient oxygen electrode for SOFC: Pr 6 O 11 infiltrated into Gd-doped ceria backbone

The praseodymium oxide, Pr 6 O 11 , is regarded as a potential electrocatalyst for the oxygen reduction reaction. Its mixed conductivity properties are characterized. At 600 °C the oxygen diffusion coefficient value is as high as 3.4 × 10 −8  cm 2  s −1 , and that of the surface exchange coefficient is 5.4 × 10 −7  cm s −1 , which supposes excellent electrocatalytic properties. The measured electronic conductivity is high enough for using this material as a SOFC cathode. Herein, praseodymium nitrate is infiltrated into Gd doped ceria (GDC) backbone and fired at 600 °C to form a composite oxygen electrode Pr 6 O 11 /GDC. Electrochemical measurements show very low polarization resistance, R p = 0.028 Ω cm 2 at 600 °C. A single cell made of a commercial Ni-YSZ/YSZ half cell and of the infiltrated cathode is able to deliver a maximum power density of 825 mW cm −2 at 600 °C. Ageing of this cell for 840 h, at 600 °C and 0.5 A cm −2 , shows a degradation rate lower than 1%.