(696f) Evolution of Cathodic Interfaces with the Solid Electrolyte Li7La3Zr2O12

While Li₇La₃Zr₂O₁₂ (LLZO) remains a promising candidate electrolyte for solid state lithium batteries, comprehensive characterizations of its stability against Li-ion cathodic materials have been lacking. Therefore, we investigated the interface between LLZO and the commonly used cathode LiMn₂O₄ (LMO) as a function of operating temperature and electrochemical cycling. Thin-film LMO cathodes were deposited by RF sputtering onto LLZO pellets to form both full and symmetric cells. The use of symmetric cells in combination with electrochemical impedance spectroscopy facilitates tracking the evolution of the interface as a function of cycling. Au-LLZO-Au and Li-LLZO-Li symmetric cells are used to provide further understanding of equivalent circuit elements, which are fit to track changes to individual cell components. Depth-profiling and STEM-EDS are used as interface-sensitive techniques to monitor interfacial changes. Finally, we test LMO-LLZO-Li full cells to demonstrate battery performance.