Synthesis of textured Li0.33La0.55TiO3 solid electrolytes by molten salt method

Abstract

Li0.33La0.55TiO3 (LLTO) with perovskite structure has very high grain conductivity. In this article, textured LLTO is synthesized by molten salt method. The X-ray diffraction (XRD) and field emission-scanning electron microscopy (FE-SEM) reveal that the reaction temperature and molten salts have effect on the template growth of LLTO. When the temperature does not reach the synthetic temperature of LLTO, some intermediate phases appear. As the temperature increases, the morphology of LLTO samples gradually changes from a rod-like structure to a sheet-like one. It is demonstrated that textured LLTO prepared by molten salt method shows highly (200) preferred orientation with a Lotgering factor of 0.66. The relative density of LLTO pellets reaches 94.9% together with a relatively high ionic conductivity of 2.70 × 10−5 S/cm. The growth mechanism of textured LLTO is discussed in terms of temperature- and molten salt-dependent diffusion of Ti elements; furthermore, the stable environment formed by LiCl–KCl molten salt can promote its preferential growth.