Ionic conductivity of Ga-doped LLZO prepared using Couette-Taylor reactor for all-solid lithium batteries

A Couette-Taylor reactor and a batch reactor were used to synthesize garnet-related LLZO materials (Li7-3xMxLa3Zr2O12, M = Ga, Al) for all-solid batteries, and the properties of the resulting samples were compared. Ga-doped LLZO synthesized with the Couette-Taylor reactor comprised cubic phase primary nanoparticles; the calculated lattice parameter and crystallite size for the Couette-Taylor and batch reactor samples were a = 12.98043 angstrom and 129.8 nm and a = 12.97568 angstrom and 394.5 nm, respectively. The parameters for the Al-doped LLZO congener synthesized with the Couette-Taylor reactor were a = 13.10758 angstrom, c = 12.67279 angstrom, and 132.5 nm. The cross-section of the Ga-doped LLZO pellet synthesized with the Couette-Taylor reactor showed a denser microstructure than that of the other pellets, with a relative density of 98%. The total ionic conductivity of the Ga-doped LLZO pellets synthesized with the Couette-Taylor reactor was 1.2-1.75 x 10(-3)S/cm at 25 degrees C. This value contrasts sharply with that of the sample from the batch reactor (3.9 x 10(-4) S/cm). This is may be related to the large size of Ga doped into the LLZO crystallite structure and the primary nanoparticles, which promoted sintering of the pellet. (C) 2017 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.