Li7La3Zr2O12 (LLZO) and its doped compounds are among the most promising solid-state electrolytes for the new generation of Li metal batteries. LLZO can host fast Li-ionic transport in its structure along with preferential crystalline planes and orientations. The materials’ electrical properties and degradation effects strictly depend on structural and microstructural features. To realize the commercialization of Li metal batteries, the high ionic conductivity of the solid-state electrolyte (SSE) material is crucial. In this MSC project, we will use electrochemical impedance spectroscopy (EIS) to characterize LLZO epitaxial thin-film materials. LLZO thin films are deposited by pulsed laser deposition (PLD). Deposition conditions and substrates are used to tune the crystallographic and microstructural features such as grain boundaries and size.