relative permittivity of the electrolytes. In order to determine the EDL capacitance, we still need to estimate the CSL. This is not straightforward, because lSL is not readily available through any direct experimental methods, and there are no ways to deduce the exact εr,SL of the Stern layer. However, some approximations were adopted following the propositions of Khademi et al. for both the Stern layer thickness and permittivity, which are within the correct order of magnitude.