Variation of ionic conductivity in a plastic-crystalline mixture
| Autor: | Reuter, D., Geiß, C., Lunkenheimer, P., Loidl, A. |
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| Rok vydání: | 2017 |
| Předmět: | |
| Zdroj: | J. Chem. Phys. 147 (2017) 104502 |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1063/1.5001946 |
| Popis: | Ionically-conducting plastic crystals are possible candidates for solid-state electrolytes in energy-storage devices. Interestingly, the admixture of larger molecules to the most prominent molecular PC electrolyte, succinonitrile, was shown to drastically enhance its ionic conductivity. Therefore, binary mixtures seem to be a promising way to tune the conductivity of such solid-state electrolytes. However, to elucidate the general mechanisms of ionic charge transport in plastic crystals and the influence of mixing, a much broader data base is needed. In the present work, we investigate mixtures of two well-known plastic-crystalline systems, cyclohexanol and cyclooctanol, to which 1 mol% of Li ions were added. Applying differential scanning calorimetry and dielectric spectroscopy, we present a thorough investigation of the phase behavior and the ionic and dipolar dynamics of this system. All mixtures reveal plastic-crystalline phases with corresponding orientational glass-transitions. Moreover, their conductivity seems to be dominated by the "revolving-door" mechanism, implying a close coupling between the ionic translational and the molecular reorientational dynamics of the surrounding plastic-crystalline matrix. In contrast to succinonitrile-based mixtures, there is no strong variation of this coupling with the mixing ratio. Comment: 8 pages, 6 figures, final version as accepted for publication |
| Databáze: | arXiv |
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