Strontium doped lithium ion garnets Li7La3Zr2O12 (LLZ) with 0.9 wt% to 8.4 wt% content of added Sr were synthesized via conventional solid-state reaction. X-ray diffraction patterns confirmed the cubic garnet structure of the sintered samples. A small amount of strontium was substituted to lanthanum in LLZ lattice. Further analysis showed SrCO3 acted as a sintering aid for cubic LLZ ceramics and significantly increased the grain size of the sintered pellets. A conductivity of 2.10 x 10(-4) S/cm at 297 K was obtained for the undoped LLZ. The total ionic conductivity reached a maximum of about 5 x 10(-4) S/cm at 297 K with an activation energy of about 0.31 eV for 1.7 wt% Sr added LIZ sintered for 20-24 Is in alumina crucible. (C) 2013 Elsevier B.V. All rights reserved.