Characterisation of Electrodes, Electrolyte and Electrode/Electrolyte Stacks Obtained by Powder Aerosol Deposition

Titelangaben

Lang, Sabrina ; Hennerici, Lukas ; Linz, Mario ; Avadanii, Diana ; Kita, Jaroslaw ; Kramer, Dominik ; Moos, Ralf ; Mönig, Rainer:
Characterisation of Electrodes, Electrolyte and Electrode/Electrolyte Stacks Obtained by Powder Aerosol Deposition.
2023
Veranstaltung: The 4th World Conference on Solid Electrolytes for Advanced Applications: Garnets and Competitors , 04.-07. September 2023 , Tromsø, Norway.
(Veranstaltungsbeitrag: Kongress/Konferenz/Symposium/Tagung , Poster )

Angaben zu Projekten

Abstract

Powder aerosol deposition (PAD) is a relatively new technique for the manufacturing of dense nanocrystalline ceramic films. PAD can be used to manufacture ceramic electrodes and electrolytes for all-solid-state batteries. Among these ceramic electrolyte Li7La3Zr2O12 (LLZO) is one of the most promising materials due to its relatively high ionic conductivity and chemical stability against lithium metal. One of the main challenges implementing LLZO into solid-state batteries are the high temperatures required for processing (e.g., sintering of a composite cathode). Recent developments demonstrate that LLZO produced by PAD requires lower temperatures to achieve high ionic conductivity. In our research within the German FestBatt Cluster we investigate how room-temperature PAD can be used for the production of solid-state batteries consisting of NMC-cathode and LLZO-electrolyte. Here, we show how the microstructure of PAD LLZO films evolves during different heat treatments and how these procedures influence the electrochemical performance. Due to the nanocrystalline structure of the PAD films, determination of the grain sizes is challenging. Different methods for the determination of the average grain size have been explored. We select ion-channelling contrast as the most suitable method to analyze the microstructure with small grain size and high number of defects. We track the evolution of the microstructure at a selected region of a sample with increasing temperatures up to 500 °C. Of great interest is the interface between the LLZO layer and the copper current collector and, subsequently, the interface between the LLZO and the lithium metal. This interface is critical for the formation of voids and dendrites. For the imaging of interfaces before and after plating of lithium, we use intermittent helium-ion microscopy (HIM). For the preparation of cross sections, conventional mechanical polishing as well as a gallium FIB including neon ion polishing (no alloying reactions with lithium) are used. Mechanical stresses within a layered thin film system can be measured by the substrate curvature technique. Mechanical forces arising during cell operation lead to a curvature that can be measured by the deflection of laser beams. We explore how this technique can be applied to thin film all-solid-state batteries und how the mechanical stress data can be used to infer fundamental electrochemical processes. Our results couple microstructure, mechanics, and electrochemistry in LLZO-based batteries and contribute to the optimization of the PAD technique towards the production of batteries with tailored microstructures.