Daniels, LindseyScott, MatthewMišković, Zoran L.2018-06-292018-06-292018-06-01https://doi.org/10.1016/j.cplett.2018.04.030http://hdl.handle.net/10012/13452The final publication is available at Elsevier via http://dx.doi.org/10.1016/j.cplett.2018.04.030 © 2018. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/We analyze the effects of dielectric decrement and finite ion size in an aqueous electrolyte on the capacitance of a graphene electrode, and make comparisons with the effects of dielectric saturation combined with finite ion size. We first derive conditions for the cross-over from a camel-shaped to a bell-shaped capacitance of the diffuse layer. We show next that the total capacitance is dominated by a V-shaped quantum capacitance of graphene at low potentials. A broad peak develops in the total capacitance at high potentials, which is sensitive to the ion size with dielectric saturation, but is stable with dielectric decrement.enAttribution-NonCommercial-NoDerivatives 4.0 InternationalGrapheneCapacitanceElectrolyteDielectric decrementSteric effectsArticle