# Simulating electrochemical systems by combining the finite field method with a constant potential electrode

## TL;DR

This paper introduces a method combining finite electric field application with constant potential electrodes in molecular dynamics to better simulate electrochemical interfaces, capturing ion adsorption and charge fluctuations.

## Contribution

It presents a novel simulation approach that enables fixed-potential electrochemical interface modeling within classical molecular dynamics frameworks.

## Key findings

- Successfully simulates electrode charge fluctuations and ion adsorption.
- Creates paired electric double layers with aligned dipoles.
- Facilitates efficient electrochemical interface simulations.

## Abstract

A better understanding of interfacial mechanisms is needed to improve the performances of electrochemical devices. Yet, simulating an electrode surface at fixed electrolyte composition remains a challenge. Here we apply a finite electric field to a single electrode held at constant potential and in contact with an aqueous ionic solution, using classical molecular dynamics. The polarization yields two electrochemical interfaces on opposite sides of the same metal slab. While the net charge on one electrode surface is the opposite of the net charge on the other, maintaining overall charge neutrality of the metal. The electrode surface charges fluctuations are compensated by the adsorption of ions from the electrolyte, forming a pair of electric double layers with aligned dipoles. This opens the way towards the efficient simulation of electrochemical interfaces using any flavor of molecular dynamics, from classical to first principles-based methods.