Sol-gel synthesis and lithium ion conduction properties of garnet-type Li ₆BaLa ₂Ta ₂O ₁₂

High lithium ion conductive garnet-type barium lanthanum lithium tantalate, Li ₆BaLa ₂Ta ₂O ₁₂ (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 Li ₆BaLa ₂Ta ₂O ₁₂, prepared by sol-gel synthesis method, shows a total Li-ion conductivity of 1.69 × 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.