Sol-gel synthesis and lithium ion conduction properties of garnet-type Li6BaLa2Ta2O12

High lithium ion conductive garnet-type barium lanthanum lithium tantalate, Li6BaLa2Ta2O12 (LLBTO), was prepared by a modified sol-gel Pechini method from the appropriate mixtures of lithium carbonate, lanthanum oxide, barium carbonate and tantalum ethoxide. The thermal decomposition of the precursor powder was investigated by TG/DTA analysis. The LLBTO precursor powders were annealed at various temperatures between 923 and 1123 K for 6 h in air. The transformation process from precursor powder to crystalline garnet-like phase was analyzed by X-ray powder diffraction (XRPD). The morphology of the powders annealed at various temperatures was investigated by scanning electron microscopy (SEM). The resultant pelletized Li6BaLa2Ta2O12, prepared by sol-gel synthesis method, shows a total Li-ion conductivity of 1.69 x 10(-5) S/cm at 298 K and an activation energy is 0.40 eV. The ionic conductivities reported in this study are slightly higher than those reported for LLBTO sample synthesized by conventional solid state synthesis route. (C) 2012 Elsevier Ltd. All rights reserved.