2021/09/28 by O. Patsahan, Patsahan, Oksana, A. Ciach +1
Engineering · Materials Science · Physics and Astronomy · #Advanced Battery Materials and Technologies #FOS: Physical sciences #Soft Condensed Matter (cond-mat.soft) #Solid-state spectroscopy and crystallography #Spectroscopy and Quantum Chemical Studies #Statistical Mechanics (cond-mat.stat-mech)
paper · pdf · doi:10.48550/arxiv.2109.13530
openalex publication_date 2021/09/28 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
A mesoscopic theory for water-in-salt electrolytes combining density functional and field-theoretic methods is developed in order to explain the unexpectedly large period of the oscillatory decay of the disjoining pressure observed in recent experiments for the LiTFSI (lithium bis(trifluoromethylsulfonyl)-imide) salt [T. S. Groves et. al., J. Phys. Chem. Lett. \bf 12,1702 (2021)]. We assumed spherical ions with different diameters, and implicit solvent inducing strong, short-range attraction between ions of the same sign. For this highly simplified model, we calculated correlation functions. Our results indicate that mesoscopic inhomogeneities can occur when the sum of the Coulomb and the water-mediated interactions between like ions is attractive at short- and repulsive at large distances. We adjusted the attractive part of the potential to the water-in-LiTFSI electrolyte, and obtained both the period and the decay rate of the correlations in a semiquantitative agreement with the experiment. In particular, the decay length of the correlations increases nearly linearly with the volume fraction of ions.