Historically, the transport phenomena of ions have been described using nonequilibrium statistical mechanics, such as the Debye-Hückel-Onsager-Falkenhagen theory. In this theory, ions are treated as Brownian particles in a continuum dielectric solvent, interacting through Coulombic forces. Since the ions are in continuous motion, the frictional force acting on an ion is proportional to its velocity. The simple Stokes law, derived from hydrodynamic theory, which states that friction increases with increasing ionic radii, fails to accurately describe small alkali and halide ions. The total friction, 𝜁 ! , is described as the sum of hydrodynamic friction, 𝜁 ! " , and dielectric friction, 𝜁 ! # , according to the following equation (𝜁 ! = 𝜁 ! " + 𝜁 ! # ). The hydrodynamic friction is proportional to the ion size and is given by Stokes law with slip boundary conditions (𝜁 ! " = 4𝜋𝜂𝑅 ! ), where Ri is the Stokes radius and η is the solvent viscosity. In continuum treatments, the dielectric friction is usually characterized by a single relaxation time