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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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Revealing the Solid‐State Electrolyte Interfacial Stability Model with Na–K Liquid Alloy
Abstract In this work, the Na–K liquid alloy with a charge selective interfacial layer is developed to achieve an impressively long cycling life with small overpotential on a sodium super‐ionic conductor solid‐state electrolyte (NASICON SSE). With this unique multi‐cation system as the platform, we further propose a unique model that contains a chemical decomposition domain and a kinetic decomposition domain for the interfacial stability model. Based on this model, two charge selection mechanisms are proposed with dynamic chemical kinetic equilibrium and electrochemical kinetics as the manners of control, respectively, and both are validated by the electrochemical measurements with microscopic and spectroscopic characterizations. This study provides an effective design for high‐energy‐density solid‐state battery with alkali Na–K anode, but also presents a novel approach to understand the interfacial chemical processes that could inspire and guide future designs.
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- Award ID(s):
- 1938833
- PAR ID:
- 10373390
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Angewandte Chemie International Edition
- Volume:
- 61
- Issue:
- 29
- ISSN:
- 1433-7851
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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