Abstract The solid electrolyte interphase (SEI) is a dynamic, electronically insulating film that forms on the negative electrode of Li+batteries (LIBs) and enables ion movement to/from the interface while preventing electrolyte breakdown. However, there is limited comparative understanding of LIB SEIs with respect to those formed on Na+and K+electrolytes for emerging battery concepts. We used scanning electrochemical microscopy (SECM) for the in situ interfacial analysis of incipient SEIs in Li+, K+and Na+electrolytes formed on multi‐layer graphene. Feedback images using 300 nm SECM probes and ion‐sensitive measurements indicated a superior passivation and highest cation flux for a Li+‐SEI in contrast to Na+and K+‐SEIs. Ex situ X‐ray photoelectron spectroscopy indicated significant fluoride formation for only Li+and Na+‐SEIs, enabling correlation to in situ SECM measurements. While SEI chemistry remains complex, these electroanalytical methods reveal links between chemical variables and the interfacial properties of materials for energy storage.
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Electrical Double Layers Modulate the Growth of Solid–Electrolyte Interphases
Solid-electrolyte interphases (SEIs), oftentimes viewed as the most important yet least understood part of alkali ion/metal batteries, remain a key bottleneck for battery design. Despite extensive research in the past few decades, to date we have only begun to unravel the structure of SEIs, while its dynamic nucleation and growth mechanism is still elusive. Here we discuss the existing progress in characterizing SEIs in the battery community, and propose that SEI growth depends critically on the electrical double layer (EDL) structure, a factor that has been largely hidden or ignored to date. We will further discuss methods for simultaneously characterizing EDL and SEIs, with a particular focus on the emerging electrochemical 3D atomic force microscopy (EC-3D-AFM) and shell-isolated nanoparticle-enhanced Raman spectroscopy (SHINERS) techniques. In the end, we will propose strategies for predictive design of electrolytes to enable controlled EDL and SEI structures and achieve desired battery performance.
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- Award ID(s):
- 2339175
- PAR ID:
- 10577181
- Publisher / Repository:
- American Chemical Society
- Date Published:
- Journal Name:
- Chemistry of Materials
- Volume:
- 36
- Issue:
- 19
- ISSN:
- 0897-4756
- Page Range / eLocation ID:
- 9156-9166
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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