Microstructure of Electrodeposited Lithium and its Evolution During Cycling when Using Metal Interlayers in "Anode-Free" Solid-State Batteries

Abstract

"Reservoir-free" construction of solid state batteries could circumvent the handling of reactive lithium metal foils and further increase the energy density. Metallic interlayers could play an important role in the homogenization of the deposited lithium layer by increasing the coverage of the deposit and additionally reducing the size of the lithium grains. To date, the influence of different interlayers and the influence of stripping on the lithium microstructure is still unknown. This work analyzes the influence of gold, silver and bismuth interlayers on the microstructure of electrodeposited lithium layers using electron backscatter diffraction (EBSD) on cross-sections prepared by broad ion-milling. In addition, partially stripped lithium layers and thus the influence of stripping on the lithium microstructure are analyzed using the mentioned interlayers. Our findings reveal that different interlayer materials result in different lithium microstructures. In addition, stripping also causes a significant change in the lithium microstructure, both in terms of grain size and grain orientation, gaining a deeper understanding of the lithium microstructure and its impact.