Synthesis and electrical transport properties of Lu2+xTi2−xO7−x/2 oxide-ion conductors

The Lu2+xTi2−xO7−x/2 (x = 0; 0.052; 0.096; 0.286; 0.44; 0.63; 33.3–49 mol% Lu2O3) nanoceramics with partly disordered pyrochlore-type structure are prepared by sintering freeze-dried powders obtained by a co-precipitation technique with 1600 °C annealing. Similar to pyrochlore-like compositions in the zirconate system, some of the new titanates are good oxide-ion conductors in air. The new solid-state electrolytes have oxide-ion conductivity in the interval of 1.0 × 10− 3 – 2.5 × 10− 3 S/cm at 740 °C in air. This value of conductivity is comparable with that of ZrO2/Y2O3 ceramics. The conductivity of Lu2+xTi2−xO7−x/2 depends on the chemical composition. The highest ionic conductivity is exhibited by nearly stoichiometric Lu2+xTi2−xO7−x/2 (x = 0.096; 35.5 mol% Lu2O3) material containing ∼ 4.8 at.% LuTi anti-site defects.