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Triflate ion association in plasticized polymer electrolytes

journal contribution
posted on 01.05.1996, 00:00 authored by A Bishop, D MacFarlane, D McNaughton, Maria ForsythMaria Forsyth
Ion association in plasticised solid polymer electrolytes (SPEs) has been monitored using FT-IR spectroscopy. The SPEs were prepared from a random co-polymer of ethylene oxide (EO) and propylene oxide (PO) and the salt lithium trifluoromethane sulfonate (lithium triflate, LiTf). Tetraethylene glycol dimethylether (tetraglyme, ε˜5) and N,N'-dimethyl formamide (DMF, ε = 36.7) were chosen as model plasticisers. Decreased ion association resulted from plasticization with DMF, indicating that the addition of a higher dielectric constant solvent increases the fraction of dissociated ions in the SPE. The incorporation of tetraglyme into these SPEs results in increased ion association, despite the similar dielectric constants of the plasticiser and polymer host. The effects of salt concentration (0.05–1.25 mol dm− 3 solvent) upon ion association in SPEs was also investigated. There appears to be a minimum in the number of “free” ions at a LiTf concentration of 0.2 mol dm− 3 solvent followed by a maximum at approximately 0.4 mol dm− 3 solvent, consistent with the molar conductivity behaviour previously observed in these electrolytes.

History

Journal

Solid state ionics

Volume

85

Issue

1-4

Pagination

129 - 135

Publisher

Elsevier

Location

Amsterdam, The Netherlands

ISSN

0167-2738

eISSN

1872-7689

Language

eng

Publication classification

C1.1 Refereed article in a scholarly journal

Copyright notice

1996, Elsevier Science B.V.