Electrical double-layer (EDL) effect close to an electrode. The Stern layer is compact and comprises ions adsorbed directly onto the electrode. Its thickness is the order of one molecule diameter. The diffuse layer is composed by ions attracted to the surface via Coulomb-forces. Its thickness is the order of 10⁻⁸ to 10⁻⁷m. The bulk is the remaining part of the channel. Picture is drawn without scales.