Solid electrolyte Li7La3Zr2O12 (LLZO) powder was successfully synthesized by co-precipitation method. The LLZO powder calcined at 850 degrees C with a tetragonal phase was confirmed by X-ray diffraction (XRD). Scanning electron microscopy (SEM) showed that the particles sizes of LLZO precursor powder were in the range of 0.5 similar to 1 mu m. LLZO pellets were sintered at different temperatures from 1150 to 1200 degrees C in air atmosphere. When the temperature was above 1150 degrees C, tetragonal LLZO would completely transform into cubic phase. The total ionic conductivity of LLZO pellet sintered at 1180 degrees C was 2.0 x 10(-4) S cm(-1) at 30 degrees C, and the activation energy was 025 eV. This result indicates that high quality LIZO solid electrolytes can be obtained by chemical co-precipitation method. (C) 2016 Elsevier B.V. All rights reserved.