Finding Infinities in Nanoconfined Geothermal Electrolyte Static Dielectric Properties and Implications on Ion Adsorption/Pairing

Abstract

Infinities should naturally occur in the dielectric responses of ionic solutions relevant to many geochemical, energy storage, and electrochemical applications at a strictly zero frequency. Using molecular dynamics simulations cross-referenced with coarse-grained Monte Carlo models, using nanoslit pore models at hydrothermal conditions, and treating confined mobile charges as polarization, we demonstrate the far reaching consequences. The dielectric permittivity profile perpendicular to the slit (ϵ⊥(z)) increases, not decreases, with ionic concentration, unlike in the more widely studied megahertz-to-gigahertz frequency range. In confined electrolytes, the divergences in ϵ⊥(z) correctly describe crossovers between bulk- and surface-dominated dielectric behavior. Nanoconfinement at low ionic concentrations changes monovalent ion energetics by 1–2 kJ/mol, but no dielectric property studied so far is universally correlated to ion adsorption or ion–ion interactions. We caution that infinities signal violation of the “electrical insulator” dielectric assumption.

Confinement-induced clustering of H2 and CO2 gas molecules in hydrated nanopores

“…27 Consequently, the central questions addressed in this work revolve around how nanoconfinement and surface chemistry modify these interactions and how these altered interactions subsequently influence gas cluster formation. Given that nanoconfinement alters many physicochemical and thermodynamic properties of the confined species compared to their characteristics in a bulk state, [28][29][30][31][32][33][34][35][36] it is reasonable to assume that nanoconfinement significantly enhances or suppresses these interactions, which is ultimately reflected in clustering of gas molecules.…”