On the La2/3-xLi3xTiO3/Al 2O3 composite solid-electrolyte for Li-ion conduction

An effective ceramic processing route including tape casting and relatively low-temperature calcination has been adopted to fabricate La _0.56Li_0.33TiO₃ (LLTO)/Al₂O ₃ composite electrolytes. Correlation among additional amount of Al₂O₃, microstructure and Li-ion conductivity of the composites is examined and evaluated. What is most interesting from X-ray diffraction and transmission electron microscopy is that LiAl₅O ₈ phase is found to form in the LLTO/Al₂O₃ composites during calcination. The present study indicates that the presence of LiAl₅O₈ has a beneficial effect of increasing ionic conductivity and decreasing activation energy. It was observed that the LLTO/10 wt% Al₂O₃ composite electrolyte exhibits a higher conductivity at bulk (~6 times) and grain boundary (~3 times) compared to pure LLTO at room temperature. An Arrhenius temperature dependence of Li-ion motion in this composite electrolyte is obtained, displaying low activation energy of 0.17 and 0.37 eV for bulk and grain boundary conduction, respectively. © 2013 Elsevier B.V. All rights reserved.