Imaging the microstructure of lithium and sodium metal in anode-free solid-state batteries using electron backscatter diffraction.

'Anode-free' or, more fittingly, metal reservoir-free cells could drastically improve current solid-state battery technology by achieving higher energy density, improving safety and simplifying manufacturing. Various strategies have been reported so far to control the morphology of electrodeposited alkali metal films to be homogeneous and dense, but until now, the microstructure of electrodeposited alkali metal is unknown, and a suitable characterization route is yet to be identified. Here we establish a reproducible protocol for characterizing the size and orientation of metal grains in differently processed lithium and sodium samples by a combination of focused ion beam and electron backscatter diffraction.

A Simple Method for the Study of Heteroionic Interface Impedances in Solid Electrolyte Multilayer Cells Containing LLZO.

Hybrid battery cells that combine a garnet-type LiLaZrO (LLZO) solid electrolyte with other solid, polymer or liquid electrolytes are increasingly investigated. In such cells with layered electrolytes, ensuring a low-resistive heteroionic interface between neighboring electrolytes is crucial for preventing major additional overpotentials during operation. Electrochemical impedance spectroscopy is frequently used to extract such parameters, usually on multilayer symmetrical model cells that contain the different electrolytes stacked in series.