<P> When an electronic conductor is brought in contact with a solid or liquid ionic conductor (electrolyte), a common boundary (interface) among the two phases appears . Hermann von Helmholtz was the first to realize that charged electrodes immersed in electrolytic solutions repel the co-ions of the charge while attracting counterions to their surfaces . Two layers of opposite polarity form at the interface between electrode and electrolyte . In 1853 he showed that an electrical double layer (DL) is essentially a molecular dielectric and stores charge electrostatically . Below the electrolyte's decomposition voltage the stored charge is linearly dependent on the voltage applied . </P> <P> This early model predicted a constant differential capacitance independent from the charge density depending on the dielectric constant of the electrolyte solvent and the thickness of the double - layer . </P> <P> This model, with a good foundation for the description of the interface, does not consider important factors including diffusion / mixing of ions in solution, the possibility of adsorption onto the surface and the interaction between solvent dipole moments and the electrode . </P> <P> Louis Georges Gouy in 1910 and David Leonard Chapman in 1913 both observed that capacitance was not a constant and that it depended on the applied potential and the ionic concentration . The "Gouy - Chapman model" made significant improvements by introducing a diffuse model of the DL . In this model the charge distribution of ions as a function of distance from the metal surface allows Maxwell--Boltzmann statistics to be applied . Thus the electric potential decreases exponentially away from the surface of the fluid bulk . </P>

Which of the following is not related to a cells ratio of surface area to volume