Open AccessMesoscopic Inhomogeneities in Concentrated Electrolytes
Author(s) -
Oksana Patsahan,
A. Ciach
Publication year - 2022
Publication title -
acs omega
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.779
H-Index - 40
ISSN - 2470-1343
DOI - 10.1021/acsomega.1c06013
Subject(s) - mesoscopic physics , ion , electrolyte , lithium (medication) , chemical physics , coulomb , chemistry , physics , condensed matter physics , thermodynamics , materials science , quantum mechanics , medicine , electrode , endocrinology , electron
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 lithium bis(trifluoromethylsulfonyl)-imide (LiTFSI) salt [T. S. Groves et al., J. Phys. Chem. Lett. 2021 , 12 , 1702]. 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 semiquantitative agreement with the experiment. In particular, the decay length of the correlations increases nearly linearly with the volume fraction of ions.