Analysis and Mitigation of Electrochemical Impedance Spectroscopy Artefacts in Four-Electrode Cells: Experimental Aspects

The analysis and minimization of the electrochemical spectroscopy impedance artefacts measured in a four-electrode cell were addressed by using bypass modification of reference and sensing electrodes and capacitor bridges. Additionally, the influence of the resistance of the reference and sensing electrodes on the measured spectra was studied. Two types of four-electrode cells, non-zero gap and zero gap, were used for electrochemical impedance spectroscopy measurements in potassium phosphate buffer solution. Different impedance values of the reference and sensing Pb/PbF2 electrodes were achieved by varying the concentration of fluoride salt in the solution used to fill the electrodes. The artefacts occurring during the measurements were successfully minimized by improving the conductance of the reference and sensing electrodes at high frequencies through a bypass. Contrary to that previously observed for a three-electrode setup, the use of capacitor bridges amplified the measured artefacts.