Electrolytes were prepared by dissolving lead, cadmium, and zinc salts (P b(N O 3 ) 2 ,Cd(N O 3 ) 2 , Zn(N O 3 ) 2 , P bCl 2 , CdCl 2 , ZnCl 2 , CdSO 4 and ZnSO 4 ≥99%, Sigma-Aldrich) in Milli-Q (MQ) water, yielding concentrations of 100 nM, 10 µM, and 10 mM. EIS measurements were conducted under open-circuit potential (OCP) conditions using a VSP300 potentiostat (Bio-Logic) housed within a Faraday cage equipped with a temperature control unit to minimize environmental noise. Prior to each measurement, a 15-minute stabilization period at OCP was employed to ensure steady-state conditions. MQ water EIS responses were recorded before and after each measurement to verify electrode integrity and confirm the absence of contamination or surface modification. Detailed measurement procedures are provided in the Supplementary Information.