In
this Perspective, we highlight recent progress and challenges
related to the integration of lithium metal anodes in solid-state
batteries. While prior reports have suggested that solid electrolytes
may be impermeable to lithium metal, this hypothesis has been disproven
under a variety of electrolyte compositions and cycling conditions.
Herein, we describe the mechanistic origins and importance of lithium
filament growth and interphase formation in inorganic and organic
solid electrolytes. Multimodal techniques that combine real and reciprocal
space imaging and modeling will be necessary to fully understand nonequilibrium
dynamics at these buried interfaces. Currently, most studies on lithium
electrode kinetics at solid electrolyte interfaces are completed in
symmetric Li–Li configurations. To fully understand the challenges
and opportunities afforded by Li-metal anodes, full-cell experiments
are necessary. Finally, the impacts of operating conditions on solid-state
batteries are largely unknown with respect to pressure, geometry,
and break-in protocols. Given the rapid growth of this community and
the diverse portfolio of solid electrolytes, we highlight the need
for detailed reporting of experimental conditions and standardization
of protocols across the community.
Despite progress in solid-state battery engineering, our understanding of the chemo-mechanical phenomena that govern electrochemical behavior and stability at solid-solid interfaces remains limited compared to solid-liquid interfaces. Here, we use operando synchrotron X-ray computed microtomography to investigate the evolution of lithium/solid-state electrolyte interfaces during battery cycling, revealing how the complex interplay between void formation, interphase growth, and volumetric changes determines cell behavior. Void formation during lithium stripping is directly visualized in symmetric cells, and the loss of contact at the interface between lithium and the solid-state electrolyte (Li 10 SnP 2 S 12) is found to be the primary cause of cell failure. Reductive interphase formation within the solid-state electrolyte is simultaneously observed, and image segmentation reveals that the interphase is redox-active upon charge. At the cell level, we postulate that global volume changes and loss of stack pressure occur due to partial molar volume mismatches at either electrode. These results provide new insight into how chemo-mechanical phenomena can impact cell performance, which is necessary to understand for the development of solid-state batteries. File list (2) download file view on ChemRxiv Manuscript Updated.pdf (1.08 MiB) download file view on ChemRxiv Supplementary Information.pdf (1.02 MiB)
We
demonstrate the growth of dendritic magnesium deposits with
fractal morphologies exhibiting shear moduli in excess of values for
polymeric separators upon the galvanostatic electrodeposition of metallic
Mg from Grignard reagents in symmetric Mg–Mg cells. Dendritic
growth is understood on the basis of the competing influences of reaction
rate, electrolyte transport rate, and self-diffusion barrier.
High-rate capable, reversible lithium metal anodes are necessary for next generation energy storage systems. In situ tomography of Li|LLZO|Li cells is carried out to track morphological transformations in Li metal electrodes. Machine learning enables tracking the lithium metal morphology during galvanostatic cycling. Nonuniform lithium electrode kinetics are observed at both electrodes during cycling. Hot spots in lithium metal are correlated with microstructural anisotropy in LLZO. Mesoscale modeling reveals that regions with lower effective properties (transport and mechanical) are nuclei for failure. Advanced visualization combined with electrochemistry represents an important pathway toward resolving non-equilibrium effects that limit rate capabilities of solid-state batteries.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.