Composite cathode with Pr doped ceria and LNF for SOFCs

摘要

To improve the performance of our standard cathode consisting of a La(Ni-Fe)O_3-Ce(Gd)O_(2-δ) active layer and a La(Ni-Fe)O_3 current collection layer, we replaced the Ce(Gd)O_(2-δ) in the active layer with Pr doped ceria (Ce(Pr)O_(2-δ)). We evaluated the cathode performance in terms of its cathode interface resistance, which was greatly improved by this replacement. When X (Pr concentration of the Ce(Pr)O_(2-δ)) in Ce_(1-x)Pr_xO_(2-δ) was increased, the interface resistance decreased monotonically and reached a value about one tenth of that for a cathode with Ce(Gd)O_(2-δ). We also investigated the influence of the Ce(Pr)O_(2-δ) composition on the high temperature properties including conductivity, thermal expansion coefficient and oxygen nonstoichiometry. The p-type electrical conductivity and oxygen nonstoichiometry increased with the Pr concentration in Ce(Pr)O_(2-δ).