Improving Continuum Models to Define Practical Limits for Molecular Models of Electrified Interfaces

We develop a continuum theory of electrolyte solutions in contact with a metal electrode, based on a generalized free energy functional, and use it to explore the structure of the electric double layer at different electrochemical conditions. The model captures the effects of specific adsorption of ions and solvent polarization, and can be applied on the same footing to cases with non-zero faradaic current, beyond the classical double-layer regime. These advances permit the prediction of peculiar character in the ion profiles at electrode potentials near the redox level, exploration of the electrochemical stability of the interface, and differentiation between the mechanisms of electron and ion transport and associated time scales. The developed methodology enables us to self-consistently determine the fundamental limits for a microscopic description of biased interfaces, in terms characteristic sizes and time scales of relevant processes, within atomistic and ab initio molecular dynamics simulations. (C) The Author(s) 2017. Published by ECS. All rights reserved.