The thermal expansion (TE) coefficients of the lithium-stable lithium-ion conducting garnet lithium lanthanum zirconium oxide (LLZ) and the effect of aluminum substitution were measured from room temperature up to 700 °C by a synchrotron-based X-ray diffraction. The typical TE value measured for the most reported composition (LLZ doped with 0.3 wt.% or 0.093 mol% aluminum) was 15.498 × 10-6 K-1, which is approximately twice the value reported for other garnet-type structures. As the Al(III) concentration has been observed to strongly affect the structure observed and the ionic conductivity, we also assessed its role on thermal expansion and noted only a small variation with increasing dopant concentration. The materials implications for using LLZ in a solid state battery are discussed.
Hubaud, A. A., Schroeder, D. J., Ingram, B. J., Okasinski, J. S., & Vaughey, J. T. (2015). Thermal expansion in the garnet-type solid electrolyte (Li7-xAlx/3)La3Zr2O12 as a function of Al content. Journal of Alloys and Compounds, 644, 804–807. https://doi.org/10.1016/j.jallcom.2015.05.067