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arXiv · 1905.12076

Ionic activity in concentrated electrolytes: solvent structure effect revisited

Amir Levy·Martin Z. Bazant·Alexei A. Kornyshev
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Abstract

We revisit the role of the local solvent structure on the activity coefficient of electrolytes with a general non-local dielectric function approach. We treat the concentrated electrolyte as a dielectric medium and suggest an interpolated formula for the dielectric response. The pure water limit is calibrated based on MD simulations and experimental data. Solving our model around a central ion, we find strong over-screening and oscillations in the potential, which are absent in the standard "primitive model" predictions. We obtain mathematically tractable closed-form expressions for the activity coefficients and show reasonable agreement with experimental data.

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Amir Levy, Martin Z. Bazant, Alexei A. Kornyshev. 2019-05-28. Ionic activity in concentrated electrolytes: solvent structure effect revisited. https://doi.org/10.1016/j.cplett.2019.136915

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