Projects per year
Abstract
Na-ion batteries are amongst the most appealing alternatives to Li-ion batteries due to a similar intercalation chemistry and lower cost. Novel Na-ion chemistries are often assessed in half cells that contain Na-metal counter and reference electrodes (Figure 1). These electrodes are highly reactive and require a passivation layer to work, which is formed from electrolyte decomposition products. Recently, however, the passivation layer of standard carbonate electrolytes on sodium metal was found to be rather instable, raising questions about the reliability of both Na-ion half cells and other low voltage anodes. [1]
This work presents a dimethoxyethane (DME) / sodium bis(fluorosulfonyl)imide (NaFSI) (2/1 (n/n)) electrolyte that forms a stable and resilient passivation layer on sodium metal, as indicated by highly reversible sodium plating/stripping. Further investigation of the passivation layers by post-mortem FTIR and 1H-NMR analysis reveals that conventional organic carbonate based electrolytes decompose to organic salts such as sodium ethyl dicarbonate. In contrast, the DME/NaFSI electrolyte forms ethereal and alkoxide species as well as inorganic salts derived from the FSI anion. These compounds ensure sodium metal passivation and thereby enable more reliable and efficient testing in Na-ion half cells.
This work presents a dimethoxyethane (DME) / sodium bis(fluorosulfonyl)imide (NaFSI) (2/1 (n/n)) electrolyte that forms a stable and resilient passivation layer on sodium metal, as indicated by highly reversible sodium plating/stripping. Further investigation of the passivation layers by post-mortem FTIR and 1H-NMR analysis reveals that conventional organic carbonate based electrolytes decompose to organic salts such as sodium ethyl dicarbonate. In contrast, the DME/NaFSI electrolyte forms ethereal and alkoxide species as well as inorganic salts derived from the FSI anion. These compounds ensure sodium metal passivation and thereby enable more reliable and efficient testing in Na-ion half cells.
Translated title of the contribution | Ein hochkonzentrierter Etherelektrolyt für effiziente Na-Ionen Halbzellen |
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Original language | English |
Publication status | Published - 27 Sept 2016 |
Event | 2nd Graz Battery Days - Graz, Austria Duration: 27 Sept 2016 → 28 Sept 2016 |
Conference
Conference | 2nd Graz Battery Days |
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Country/Territory | Austria |
City | Graz |
Period | 27/09/16 → 28/09/16 |
Fields of Expertise
- Advanced Materials Science
Treatment code (Nähere Zuordnung)
- Basic - Fundamental (Grundlagenforschung)
Projects
- 1 Finished
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AIMS - Advanced and Innovative Materials for Electrochemical Energy Storage
Uhlig, F. & Wilkening, H. M. R.
1/07/14 → 31/08/18
Project: Research project