PREPARATION AND PROPERTIES OF YTTRIUM-DOPED LITHIUM ZIRCONATE

Ceramic samples of Li2+xYxZr1-xO3 w th x = 0, 0.01, 0.05, and 0.1 were prepared by conventional methods. The crystal structures and microstructures of the ceramic samples were studied using x-ray diffraction, infrared spectra, and scanning electron microscopy The results show that a solid solution of Li2+xYxZr1-xO3 was formed when x was not larger than 0. 05 and a second phase appeared in the solid solution when x was equal to 0.1. The sinterability of Li2ZrO3 improved greatly with addition of yttrium from 80.8% theoretical density (TD.) for the sample without yttrium to 94.6% T.D. for the sample with x = 0.05; the grain size decreased significantly with the formation of the solid solution. The total lithium ion conductivity increased slightly, from 3.9 x 10(-6) S/cm for pure Li2ZrO3 to 5.0 x 10(-6) S/cm for the sample with x = 0.05 at 400-degrees-C and the corresponding conduction activation energy decreased from 0.99 to 0.92 eV Based on the effective medium theory, the conductivity increase in the solid solution crystal was estimated to be 3% for x = 0.05 compared with the pure Li2ZrO3 crystal.