Synthesis of lithium garnet oxides of the compositions series Li_7-xLa₃Zr_2-xTa_xO₁₂

In order to obtain a safe, reliable, long-lived battery system without use of flammable, volatile, and relatively unstable organic liquid-based electrolytes, lithium garnet oxides with formulas Li_7-xLa₃Zr_2-xTa_xO₁₂ (x=0.2-1) were synthesized by the solid state reaction method. Single cubic phases were observed in the composition x range between 0.2 and 1. The lattice parameters decreased with the addition of Ta due to the smaller ionic radius of Ta⁵⁺ compared with that of Zr⁴⁺, following the Vegard’s law. The total conductivity of the x = 0.3 composition is 6.03×10^-5 S·cm^-1 at room temperature with an activation energy of 0.30 eV. These lithium garnet oxides exhibit lithium ionic transport that is relevant to lithium battery application.