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Lithium doped N-methyl-N-ethylpyrrolidiniumbis(trifluoromethanesulfonyl)amide fast-ion conducting plastic crystals

journal contribution
posted on 01.01.2000, 00:00 authored by Maria ForsythMaria Forsyth, J Huang, D MacFarlane
The incorporation of dopant levels of lithium ions (0.5 to 9.3% by mole) in the N-methyl-N-ethylpyrrolidinium bis(trifluoromethanesulfonyl)amide (P12TFSA) plastic crystalline phase results in increases in the solid state ionic conductivity of more than 3 orders of magnitude at 298 K. Conductivities as high as 10−-4 S cm−1 at 323 K have been measured in these doped plastic crystal phases. These materials can therefore be classified as fast-ion conductors. Higher levels of Li only marginally increase the conductivity, up to around 33 mol%, followed by a slight decrease to 50 mol%. Thermal analysis behaviour has allowed the partial development of the binary phase diagram for the LiTFSA–P12TFSA system between 0–50 mol% LiTFSA, which suggests the presence of a solid solution single phase at concentrations less than 9.3 mol% LiTFSA. There is also strong evidence of eutectic behaviour in this system with a eutectic transition temperature around 308 K at 33 mol% LiTFSA. A model relating ionic conduction to phase behaviour in this system is presented. The increased conductivity upon doping has been associated with lithium ion motion via7Li solid state NMR linewidth measurements.

History

Journal

Journal of materials chemistry

Volume

10

Issue

10

Pagination

2259 - 2265

Publisher

Royal Society of Chemistry

Location

Cambridge, England

ISSN

0959-9428

eISSN

1364-5501

Language

eng

Publication classification

C1.1 Refereed article in a scholarly journal

Copyright notice

2000, Royal Society of Chemistry