Operando SEM observations of lithium-metal anodes during dissolution and deposition through LLZO

Title data

Lang, Sabrina ; Avadanii, Diana ; Kramer, Dominik ; Hennerici, Lukas ; Linz, Mario ; Kita, Jaroslaw ; Moos, Ralf ; Mönig, Reiner:
Operando SEM observations of lithium-metal anodes during dissolution and deposition through LLZO.
2024
Event: Solid-State Batteries VI : an International Bunsen Discussion Meeting , Nov 13-15, 2024 , Frankfurt a. Main, Germany.
(Conference item: Conference , Poster )

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Abstract in another language

Solid-state batteries (SSB) with lithium metal promise higher energy densities compared to conventional lithium-ion batteries. To bring forward this technology, efficient ways to produce electrode stacks need to be developed and stable interfaces between lithium metal and inorganic solid electrolytes have to be established. Here, we focus on the observation of interface processes during cell operation. Our electrolyte layers are fabricated using powder-aerosol-deposition (PAD) at RT. To produce reservoir-free cells, LLZO layers with thicknesses of 30 μm are deposited on copper substrates. We then pressed small lithium electrodes with diameters as small as 200 μm on the LLZO and performed galvanostatic experiments inside the SEM with very small currents (~ 6 nA, 20 μA/cm²). The operating Li|LLZO|Cu stack was imaged in top view to observe the morphology of the lithium in detail. Our operando SEM images show that the dissolution and deposition of lithium-metal electrodes are not necessarily reversible processes. Observations of electrode stacks with varying heat treatments show clear differences in the evolution of the lithium metal and indicate the importance of the Li|LLZO interface and the microstructure of lithium. The fundamental mechanisms of lithium metal dissolution and deposition are expected to be crucial for the reliability of SSBs. Further operando SEM investigations will be needed in order to better characterize, understand, and eventually minimize the degradation of metallic electrodes in SSB.