These values for both negative and positive charged surfaces are presented in Table . As shown before , the values remained relatively constant despite varying ionic concentrations, resulting in a negligible change in . This suggests that the increase in numbers of ions in the first adsorption layer has a limited effect on , but it does result in a reduction in the value of . All values of across various ionic concentrations (less than 5 μF cm -2 ) lie within the range of those reported for aqueous LiCl solutions on HOPG (less than 8 μF cm -2 for positive potentials depending on electrolyte concentration) at similar surface charges (i.e, ca. +1.3 V relative to the potential of the neutral surface) . The differences most probably arise from the decreased number of DOS near the Fermi level in graphene and the pseudo-capacitive contributions (i.e., adsorption of Cl -) on HOPG at increased positive potentials.