Preparation and Properties of Yttrium‐Doped Lithium Zirconate

Ceramic samples of Li2+xYxZr1−xO3 with 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 (T.D.) 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 3.9×10−6S/cm for pure Li2ZrO3 to 5.0×10−6S/cm for the sample with x=0.05 at 400°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.