Synthesis and Conductivity Measurement of Lanthanum Zirconate Doped with Rare Earth Dopants

In this work, La 2 Zr 2 O 7 with a pyrochlore structure was doped with Sc, Y, Nd, Sm and Gd into its Zr-site to investigate the dependence of conduction behavior on the dopant. A systematic study was also performed to study the relationship between Y content and the proton conductivity. The results revealed that La 2 Zr 2 O 7 doped with Y had higher conductivity, compared with those doped with Sc, Nd, Sm and Gd. Among the samples doped with various content of Y, La 2 (Zr 0.9 Y 0.1 ) 2 O 7−δ was identified to have a single pyrochlore phase, and exhibited the highest bulk conductivity of 3.68 × 10 −4 Scm −1 at 600°C in wet H 2 . But such value is still not enough for the application as an electrolyte in fuel cells. Poor capability for water incorporation is one of the reasons restricting a further increase of the proton conductivity.