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Lithium ion mobility in poly(vinyl alcohol) based polymer electrolytes as determined by 7Li NMR spectroscopy

journal contribution
posted on 01.04.1998, 00:00 authored by H Every, F Zhou, Maria ForsythMaria Forsyth, D MacFarlane
Solvent-free polymer electrolytes based on poly(vinyl alcohol) (PVA) and LiCF3SO3 have shown relatively high conductivities (10−8-10−4 S cm−1), with Arrhenius temperature dependence below the differential scanning calorimeter (DSC) glass transition temperature (343 K). This behaviour is in stark contrast to traditional polymer electrolytes in which the conductivity reflects VTF behaviour. 7Li nuclear magnetic resonance (NMR) spectroscopy has been employed to develop a better understanding of the conduction mechanism. Variable temperature NMR has indicated that, unlike traditional polymer electrolytes where the linewidth reaches a rigid lattice limit near Tg, the lithium linewidths show an exponential decrease with increasing temperature between 260 and 360 K. The rigid lattice limit appears to be below 260 K. Consequently, the mechanism for ion conduction appears to be decoupled from the main segmental motions of the PVA. Possible mechanisms include ion hopping, proton conduction or ionic motion assisted by secondary polymer relaxations.

History

Journal

Electrochimica acta

Volume

43

Issue

10-11

Pagination

1465 - 1469

Publisher

Elsevier Science Pub. Co.

Location

New York, N.Y.

ISSN

0013-4686

eISSN

1873-3859

Language

eng

Publication classification

C1.1 Refereed article in a scholarly journal

Copyright notice

1998, Elsevier Science Ltd.