Here, η is the viscosity of the fluid and R H is the hydrodynamic radius of the particle. Under a vehicular diffusion mechanism, an ion's hydrodynamic radius increases to effectively include the size of its first solvation shell, resulting in slower diffusion. While the SES equation cannot be quantitatively applied to ion transport in these confined systems, classifying transport as vehicular or structural provides a useful qualitative lens for interpreting transport trends.