Phase Formation during Solid State Synthesis of Lithium Ion Conducting Garnet from Nitrate and Carbonate Precursors

Abstract

In a previous study, the solid state synthesis of Li7La3Zr2O12 (LLZO) has been explored by neutron diffraction (ND) showing numerous intermediate phases present during heating, however no consideration was made for alternative solid state synthesis precursor materials. With alternative precursor materials, the intermediate phases that are formed may be changed, and the temperature required for synthesis may be reduced. Furthermore, a change in precursor materials can reduce or eliminate potential undesirable phases or contaminants in the final product. In this study, the synthesis of LLZO is explored by both neutron diffraction and mass spectroscopy of the flow gas, comparing solid state synthesis with either Li2CO3 or LiNO3 as the lithium precursor. Intermediate phases are examined as a function of temperature from RT to 800°C. It was demonstrated that the temperature for solid state synthesis of LLZO may be reduced by changing the lithium precursor choice from Li2CO3 to LiNO3, and the change in precursor results in a change of the intermediate phases observed. The work was supported by the U.S. Department of Energy, Office of Science, Materials Sciences and Engineering Division.