Electronic screening using a virtual Thomas-Fermi fluid for predicting wetting and phase transitions of ionic liquids at metal surfaces

Ionic and dipolar liquids display unexpected behaviours, especially in confinement, that are relevant to energy storage, electrochemistry and catalysis. An approach that involves electronic screening while capturing molecular aspects of interfacial fluids is now proposed. Of relevance to energy storage, electrochemistry and catalysis, ionic and dipolar liquids display unexpected behaviours-especially in confinement. Beyond adsorption, over-screening and crowding effects, experiments have highlighted novel phenomena, such as unconventional screening and the impact of the electronic nature-metallic versus insulating-of the confining surface. Such behaviours, which challenge existing frameworks, highlight the need for tools to fully embrace the properties of confined liquids. Here we introduce a novel approach that involves electronic screening while capturing molecular aspects of interfacial fluids. Although available strategies consider perfect metal or insulator surfaces, we build on the Thomas-Fermi formalism to develop an effective approach that deals with any imperfect metal between these asymptotes. Our approach describes electrostatic interactions within the metal through a 'virtual' Thomas-Fermi fluid of charged particles, whose Debye length sets the screening length lambda. We show that this method captures the electrostatic interaction decay and electrochemical behaviour on varying lambda. By applying this strategy to an ionic liquid, we unveil a wetting transition on switching from insulating to metallic conditions.

Automated summary

Ionic and dipolar liquids exhibit unexpected behaviors in confinement, particularly relevant to energy storage, electrochemistry, and catalysis. A new approach is introduced that involves electronic screening while capturing the molecular aspects of interfacial fluids, addressing the need for tools to fully understand the properties of confined liquids. This method, based on the Thomas-Fermi formalism, effectively describes electrostatic interactions within imperfect metals, showcasing the decay of electrostatic interactions and electrochemical behavior.