A fundamental stumbling block for advancing energy storage technologies is lack of detailed knowledge of active materials interfaces – a vital component of any functional combination of two materials. It is the characteristic size of interfaces as well as their non-additive, emergent, from the bulk properties of comprising materials, behavior that requires the means to understand, probe and control such interfaces at the molecular scale. Along that road, the main obstacle is the lack of a uniform atomistic methodology that would enable the self-consistent description of both the electronic and molecular degrees of freedom for electrochemical interfaces at capacitive and faradaic regimes. Currently, there are several approaches to the description of biased interfaces at the molecular scale. Common problem for these approaches is the unrealistic molecular configurations of the interfaces and the poor connection to the thermodynamic equilibrium. In contrast, continuum models provide a better description of the thermodynamic properties but lack atomistic details especially when specific non-electrostatic interactions play a significant role. In this paper we develop a hybrid ab initio-continuum methodology of modeling biased interfaces and apply it to study the electrochemical dissolution of a metal in a “model system” – a gold electrode in contact with aqueous halide electrolytes containing specifically adsorbing ions. We show how ab initio MD schemes could be combined with continuum models in a self-consistent fashion and demonstrate a good agreement between experimentally and theoretically derived thermodynamic characteristics, such as the adsorption isotherm and the bias dependent ion surface coverage. The methodology enables the access to the molecular structure of the electric double layer - the necessary prerequisite for interpretation of spectroscopic data.

Hybrid methodology of modeling of the electrochemical dissolution of gold in the presence of specifically adsorbing ions

255th National Meeting (2018)

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