Influence of the electrolyte film thickness on charge dynamics of ionic liquids in ionic electroactive devices

Jun Hong Lin, Yang Liu, Q. M. Zhang

    Research output: Contribution to journalArticle

    14 Scopus citations

    Abstract

    Developing advanced ionic electroactive devices such as ionic actuators and supercapacitors requires the understanding of ionic diffusion and drifting processes, which depend on the distances over which the ions travel, in these systems. The charge dynamics of [C 4mim][PF 6] ionic liquid films and Aquivion membranes with 40 wt % [C 2mim][TfO] were investigated over a broad film thickness (d) range. It was found that the double layer charging time τ DL follows the classic model τ DL = λ Dd/(2D) very well, where D is the diffusion coefficient and λ D the Debye length. In the longer time regimes (t ≫ τ DL) where diffusion dominates, the charge dynamics become voltage dependent. For low applied voltage, the later stage charge process seems to follow the d 2 dependence. However, at high voltages (>0.5 V) in which significant device responses occur, the charging process does not show d 2 dependence so that τ diff = d 2/(4D), corresponding to the ion diffusion from the bulk region, was not observed.

    Original languageEnglish (US)
    Pages (from-to)2050-2056
    Number of pages7
    JournalMacromolecules
    Volume45
    Issue number4
    DOIs
    StatePublished - Feb 28 2012

    All Science Journal Classification (ASJC) codes

    • Organic Chemistry
    • Polymers and Plastics
    • Inorganic Chemistry
    • Materials Chemistry

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