Dynamic Response of Ion Transport in Nanoconfined Electrolytes

Abstract

Ion transport in nanoconfined electrolytes exhibits nonlinear effects caused by large driving forces and pronounced boundary effects. An improved understanding of these impacts is urgently needed to guide the design of key components of the electrochemical energy systems. Herein, we employ a nonlinear Poisson−Nernst−Planck theory to describe ion transport in nanoconfined electrolytes coupled with two sets of boundary conditions to mimic different cell configurations in experiments. A peculiar nonmonotonic charging behavior is discovered when the electrolyte is placed between a blocking electrode and an electrolyte reservoir, while normal monotonic behaviors are seen when the electrolyte is placed between two blocking electrodes. We reveal that impedance shapes depend on the definition of surface charge and the electrode potential. Particularly, an additional arc can emerge in the intermediate-frequency range at potentials away from the potential of zero charge. The obtained insights are instrumental to experimental characterization of ion transport in nanoconfined electrolytes.

To Pair or not to Pair? Machine-Learned Explicitly-Correlated Electronic Structure for NaCl in Water

“…Recent work has shown the assembly of confined ions in solution into long chains under an electric field, resulting in the so-called "memristor" effect, 99 for which accurate atomistic insights are urgently needed. 100 ■ METHODS Machine Learning Potential. MLPs provide a direct mapping between a structure and its energy and forces, bypassing the computationally costly step of solving the Schrodinger equation for each time step of a simulation.…”