Local Structures in PEO-[C2mim]CF3SO3 Electrolytes Used in Electrochemical Double-Layer Capacitors

Polymer electrolytes containing room-temperature ionic liquids have tremendous potential for use in electrochemical double-layer capacitors. In this report, the local structure of one family of ionic-liquid-based polymer electrolytes (PEO complexed with 1-ethyl-3-methylimidazolium trifluoromethanesu...

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Bibliographic Details
Published in:ECS transactions 2008-11, Vol.13 (17), p.3-11
Main Author: Burba, Christopher M.
Format: Article
Language:English
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Summary:Polymer electrolytes containing room-temperature ionic liquids have tremendous potential for use in electrochemical double-layer capacitors. In this report, the local structure of one family of ionic-liquid-based polymer electrolytes (PEO complexed with 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, [C2mim]CF3SO3) is correlated to trends in the conductivity and thermal properties of the materials. Conductivities dramatically increase as the mole fraction of the ionic liquid is increased in the polymer electrolyte. Concomitantly, melting point onset temperatures for PEO decrease with increasing amounts of ionic liquid. IR and Raman spectroscopy suggest that the [C2mim]+ cations are weakly coordinated by oxygen atoms of the polymer backbone, and there is some degree of ionic association at higher mole fractions. The lack of strong PEO-[C2mim]+ interactions might explain, in part, why this system has much higher conductivities compared to other PEO-MCF3SO3 (M = Li, Na, K, etc.) polymer electrolytes at equivalent salt compositions.
ISSN:1938-5862
1938-6737
DOI:10.1149/1.3039762