Evaluating continuum solvation models for the electrode-electrolyte interface: challenges and strategies for improvement

TL;DR

This paper critically evaluates continuum solvation models for electrode-electrolyte interfaces, revealing their limitations in modeling metal surfaces and proposing reparameterization to enhance accuracy in electrochemical simulations.

Contribution

It identifies key deficiencies of existing models for metal surfaces and introduces reparameterization strategies to improve their predictive accuracy in electrochemical contexts.

Findings

Most continuum models undersolvate metal surfaces.

Reparameterization improves surface charge predictions.

Models retain utility for molecular and ionic solvation.

Abstract

Ab initio modeling of electrochemical systems is becoming a key tool for understanding and predicting electrochemical behavior. Development and careful benchmarking of computational electrochemical methods are essential to ensure their accuracy. Here, using charging curves for an electrode in the presence of an inert aqueous electrolyte, we demonstrate that most continuum models, which are parameterized and benchmarked for molecules, anions, and cations in solution, undersolvate metal surfaces, and underestimate the surface charge as a function of applied potential. We examine features of the electrolyte and interface that are captured by these models, and identify improvements necessary for realistic electrochemical calculations of metal surfaces. Finally, we reparameterize popular solvation models using the surface charge of Ag(100) as a function of voltage to find improved accuracy for metal surfaces without significant change in utility for molecular and ionic solvation.