Efficient electron open boundaries for simulating electrochemical cells

TL;DR

This paper introduces an efficient method for simulating electrochemical cells with open electron boundaries, enabling molecular dynamics that account for electron exchange driven by ionic drift and diffusion.

Contribution

It presents a new limiting form for electron open boundaries suitable for molecular dynamics in electrochemical simulations, improving computational efficiency.

Findings

Successfully simulates a parallel plate capacitor with electron exchange.

Demonstrates capability with tight binding simulations.

Applicable when current is driven by ionic drift and diffusion.

Abstract

Non-equilibrium electrochemistry raises new challenges for atomistic simulation: we need to perform molecular dynamics for the nuclear degrees of freedom with an explicit description of the electrons, which in turn must be free to enter and leave the computational cell. Here we present a limiting form for electron open boundaries that applies when the magnitude of the electric current is determined by the drift and diffusion of ions in solution, and which is sufficiently computationally efficient to be used with molecular dynamics. We demonstrate its capabilities by way of tight binding simulations of a parallel plate capacitor with and without a dimer situated in the space between the plates.