The distribution of the anions in the interphase region IN is modulated by the applied A key prediction of the model in Supplementary Section S7 is that for monovalent aqueous anions, -𝑧 = -1, the peak shape is symmetric (blue curve) as described by Supplementary Equation S14 and illustrated in Fig. (ii). Meanwhile, for divalent aqueous anions, -𝑧 = -2, the peak shape is asymmetric (black curve), see Supplementary Equation S15 and Fig. (ii). The shape of the latter peak is in very good agreement with the shape of the peak  experimentally observed when using sulfuric acid as the aqueous electrolyte, see Fig. .