Molecular mobility and Li+ conduction in polyester copolymer ionomers based on poly(ethylene oxide)

Daniel Fragiadakis, Shichen Dou, Ralph H. Colby, James Runt

Research output: Contribution to journalArticlepeer-review

131 Scopus citations

Abstract

We investigate the segmental and local dynamics as well as the transport of Li+ cations in a series of model poly(ethylene oxide)-based single-ion conductors with varying ion content, using dielectric relaxation spectroscopy. We observe a slowing down of segmental dynamics and an increase in glass transition temperature above a critical ion content, as well as the appearance of an additional relaxation process associated with rotation of ion pairs. Conductivity is strongly coupled to segmental relaxation. For a fixed segmental relaxation frequency, molar conductivity increases with increasing ion content. A physical model of electrode polarization is used to separate ionic conductivity into the contributions of mobile ion concentration and ion mobility, and a model for the conduction mechanism involving transient triple ions is proposed to rationalize the behavior of these quantities as a function of ion content and the measured dielectric constant.

Original languageEnglish (US)
Article number064907
JournalJournal of Chemical Physics
Volume130
Issue number6
DOIs
StatePublished - 2009

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

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