Effect of Dopants on Low-Temperature Preparation of Garnet-type Cubic Solid Electrolyte Powders

Abstract

In this study, we focused on the low-temperature preparation of the typical Garnet-type cubic solid electrolyte powders of lithium lanthanum zirconate (LLZO) with new dopants. We chose the new dopants of Mg and Sr to stabilize the cubic phase by different preparation methods. One is the solid state reaction with a wet chemical coating of Li source, and the other is the all wet chemical processing of so called modified sol-gel method. As a result, we successfully prepared cubic LLZO powders with Mg and Sr dopants by the modified sol-gel method at lower temperature. In addition, new dopants affected the stability of the cubic phase if compared with the other dopants such as Al and Ta. The modified sol-gel method was the powerful tool to stabilize the cubic phase because of the high homogeneity of a precursor at the molecular level by the suitable molecular-design of the precursor solution.