Finite-field DFTMD modelling of protonic double layers and beyond

Oxide-electrolyte interfaces are universally present in electrochemistry, electrocatalysis, geochemistry as well as colloid science. The surface charge of all these interfaces is controlled by the pH of the electrolyte solution and this leads to the formation of electric double layers by deprotonation of adsorbed water molecules or protonation of the oxide surfaces [1]. Moreover, the oxide surface can be polarized under electrochemical conditions. Therefore, how to model polarized oxide surfaces with atomistic simulation is an outstanding question. Here, I will first discuss our recent progress on modelling the protonic double layer at metal-oxide/electrolyte interfaces [2-3] using finite-field density-functional theory-based molecular dynamics (DFTMD) simulations [4]. Then, this is followed by our new effort on introducing finite-field coupling in modelling electrified interfaces via machine-learning the charge response kernel with PiNet-chi [5-6].