Mechanism of Conductivity Relaxation in Liquid and Polymeric Electrolytes: Direct Link between Conductivity and Diffusivity.
Combining broadband impedance spectroscopy, differential scanning calorimetry, and nuclear magnetic resonance we analyzed charge and mass transport in two polymerized ionic liquids and one of their monomeric precursors. In order to establish a general procedure for extracting single-particle diffusivity from their conductivity spectra, we critically assessed several approaches previously employed to describe the onset of diffusive charge dynamics and of the electrode polarization in ion conducting materials. Based on the analysis of the permittivity spectra, we demonstrate that the conductivity relaxation process provides information on ion diffusion and the magnitude of cross-correlation effects between ionic motions. A new approach is introduced which is able to estimate ionic diffusivities from the characteristic times of conductivity relaxation and ion concentration without any adjustable parameters. This opens the venue for a deeper understanding of charge transport in concentrated and diluted electrolyte solutions.
Department of Chemistry, University of Tennessee , Knoxville, Tennessee 37996, United States.|Fakultät Physik, Technische Universität Dortmund , D-44221 Dortmund, Germany.
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Gainaru
Department of Physics and Astronomy, University of Tennessee , Knoxville, Tennessee 37996, United States.
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Stacy
Chemical Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States.
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Bocharova
Department of Physics & Astronomy, Hunter College of The City University of New York , New York, New York 10065, United States.
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Gobet
Department of Physics and Astronomy, University of Tennessee , Knoxville, Tennessee 37996, United States.
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Holt
Chemical Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States.
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Saito
Department of Physics & Astronomy, Hunter College of The City University of New York , New York, New York 10065, United States.
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Greenbaum
Department of Chemistry, University of Tennessee , Knoxville, Tennessee 37996, United States.|Chemical Sciences Division, Oak Ridge National Laboratory , Oak Ridge, Tennessee 37831, United States.
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Sokolov