Extended Nernst–Planck Equation Incorporating Partial Dehydration Effect

Novel ionic transporting phenomena emerge as nanostructures approach the molecular scale. At the sub-2 nm scale, widely used continuum equations, such as the Nernst–Planck equation, break down. Here, we extend the Nernst–Planck equation by adding a partial dehydration effect. Our model agrees with the reported ion fluxes through graphene oxide laminates with sub-2 nm interlayer spacing, outperforming previous models. We also predict that the selectivity sequences of alkali metal ions depend on the geometries of the nanostructures. Our model opens a new avenue for the investigation of the underlying mechanisms in nanofluidics at the sub-2 nm scale.