Document Type
Article
Original Publication Date
2020
Journal/Book/Conference Title
J. Phys. Chem. C
Volume
124
First Page
23433
DOI of Original Publication
https://doi.org/10.1021/acs.jpcc.0c07184
Date of Submission
May 2022
Abstract
Pressure-driven permeation of water in a poorly wettable material results in a conversion of mechanical work into surface free energy representing a new form of energy storage, or absorption. When water is replaced by a concentrated electrolyte solution, the storage capacity of a nanoporous medium becomes comparable to high-end supercapacitors. The addition of salt can also reduce the hysteresis of the infiltration/expulsion cycle. Our molecular simulations provide a theoretical perspective into the mechanisms involved in the process, and underlying structures and interactions in compressed nanoconfined solutions. Specifically, we consider aqueous NaCl in planar confinements of widths of 1.0 nm and 1.64 nm and pressures of up to 3 kbar. Open ensemble Monte Carlo simulations utilizing fractional exchanges of molecules for efficient additions/removal of ions have been utilized in conjunction with pressure-dependent chemical potentials to model bulk phases under pressure. Confinements open to these pressurized bulk, aqueous electrolyte phases show reversibility at narrow pore sizes, consistent with experiment, as well as strong hysteresis at both pore size. The addition of salt results in significant increases in the solid/liquid interfacial tension in narrower pores and associated infiltration and expulsion pressures. These changes are consistent with strong desalination effects at the lower pore size observed irrespective of external pressure and initial concentration.
Is Part Of
VCU Chemistry Publications
Comments
This is the author's manuscript of the article published in Journal of Physical Chemistry C, 2020, 124, 42, 23433–23445. DOI: https://doi.org/10.1021/acs.jpcc.0c07184