(Invited) The Electric Double Layer Revisited from an Atomistic Perspective

Abstract

At the interface between two conducting phases, an electric double layer (EDL) forms. In interfacial electrochemistry, such an EDL is present at the interface between the electrode and the electrolyte. The structure of the EDL can be crucial for all processes that occur at such interfaces, for example in electrochemical energy conversion and storage. Yet, it is fair to say that our understanding of the structure of the EDL is still limited and mainly based on concepts that are more than one hundred years old. In this contribution, I will focus on relatively simple interfaces between metallic electrodes and aqueous electrolytes [1] from a conceptual and from a quantum chemical atomistic perspective. I will discuss how elecrochemically control parameter such as the electrode potential and pH values can enter a first-principles description of electrochemical interfaces. Furthermore, I will present examples in which the explicit consideration of the electrochemical environment is not necessary in order to faithfully reproduce adsorbate structures on metal electrodes as a function of the electrochemical control parameters [2]. In addition, I will critically discuss the properties of electrochemical interfaces that correspond to observables from an atomistic perspective.[1] A. Groß and S. Sakong, Ab initio simulations of water/metal interfaces, Chem. Rev. 2022, 122, 10746.[2] A. Groß, Reversible vs. standard hydrogen electrode scale in interfacial electrochemistry from a theoretician's atomistic point of view, J. Phys. Chem. C 2022, 126, 11439.