title: The electric double-layer differential capacitance at and near zero surface charge for a restricted primitive model electrolyte.
abstract: The behavior of the differential capacitance of a planar electric double layer containing a restricted primitive model electrolyte in the neighborhood of zero surface charge is investigated by theory and simulation. Previous work has demonstrated that at zero surface charge the differential capacitance has a minimum for aqueous electrolytes at room temperature but can have a maximum for molten salts and ionic liquids. The transition envelope separating the two situations is found for a modified Poisson-Boltzmann theory and a Poisson-Boltzmann equation corrected for the exclusion volume term. Good agreement is found between simulation and the modified Poisson-Boltzmann theory in the neighborhood of the envelope at the reduced temperature of 0.8, while the exclusion volume corrected Poisson-Boltzmann theory shows correct qualitative trends.
authors.affiliation: Department of Physical Chemistry, Faculty of Chemistry, Adam Mickiewicz University, Grunwaldzka 6, 60-780 Poznan, Poland.
authors.forename: Stanislaw
authors.initials: S
authors.lastname: Lamperski
authors.forename: Christopher W
authors.initials: CW
authors.lastname: Outhwaite
authors.forename: Lutful B
authors.initials: LB
authors.lastname: Bhuiyan