화학공학소재연구정보센터
Journal of Power Sources, Vol.302, 291-297, 2016
Multistep sintering to synthesize fast lithium garnets
A multistep sintering schedule is developed to synthesize Li7La3Zr2O12 (LLZO) doped with 0.2 mol% Al3+. The effect of sintering steps on phase, relative density and ionic conductivity of Al-doped LLZO has been evaluated using powder X-Ray diffraction (XRD), scanning electron microscopy (SEM), Al-27 magic spinning nuclear magnetic resonance (NMR) spectroscopy and electrochemical impedance spectroscopy (EIS). The results show that by holding the sample at 900 degrees C for 6 h, the mixture of tetragonal and cubic garnet phases are obtained; by continuously holding at 1100 degrees C for 6 h, the tetragonal phase completely transforms into cubic phase; by holding at 1200 degrees C, the relative density increases without decomposition of the cubic phase. The Al-LLZO pellets after multistep sintering exhibit cubic phase, relative density of 94.25% and ionic conductivity of 4.5 x 10(-4) S cm(-1) at room temperature. Based on the observation, a sintering model is proposed and discussed. (C) 2015 Elsevier B.V. All rights reserved.