Origin of Asymmetric Electric Double Layers at Electrified Oxide/Electrolyte Interfaces

The structure of electric double layers (EDLs) dictates the chemistry and physics electrified interfaces, differential capacitance is key property for characterizing EDLs. Here we develop a theoretical model computing Helmholtz CH oxide–electrolyte interfaces using density functional theory-based finite-field molecular dynamics simulations. It found that dipole interfacial adsorbed groups (i.e., water molecule, hydroxyl ion, proton) at SnO2(110)/NaCl significantly modulates layer potential which leads to asymmetric distribution CH. We also find dissociative adsorption prefers inner sphere binding counterions, in turn higher capacitance, compared with nondissociative case interface. This work provides interpretation EDLs seen experimentally range metal oxides/hydroxides.