Properties of La_2-xPr_xNiO₄ cathode for intermediate-temperature solid oxide fuel cells

A series of K₂NiF₄-type compounds, La _2-xPr_xNiO₄ (x = 0, 0.6, 1.0, 1.4, and 2.0), were synthesized by solid state reaction for use as cathodes in an intermediate-temperature (500700° C) solid oxide fuel cell (IT-SOFC). La_2-xPr_xNiO₄ (x = 0 and 0.6) crystallize in the Fmmm space group, while La_2-xPr_xNiO₄ (x = 1.0, 1.4, and 2.0) belong to the Bmab space group. The electrical conductivity increased by Pr doping and La_2-xPr_xNiO₄ (x = 0.6, 1.0, and 1.4) exhibited electrical conductivities similar to one another while Pr₂NiO₄ had the highest. Single test-cells consisting of samarium oxide doped ceria (SDC) as an electrolyte, NiSDC cermet as an anode and La_2-xPr_xNiO₄ as a cathode, were fabricated for measurements of cell performance at 500700° C. Current interruption measurements revealed that the overpotential losses mainly decreased with increasing Pr content. Pr₂NiO₄ was found to exhibit the best cathode characteristics; maximum test-cell power densities of 14.1, 45.1, and 104.4mW/cm² were obtained at 500, 600, and 700°C, respectively.