Noise Phenomena in Electrochemical Impedance Spectroscopy of Polymer Electrolyte Membrane Electrolysis Cells

In this study, the origin of noise in electrochemical impedance spectroscopy (EIS) spectra measured on a variety of polymer electrolyte membrane electrolysis cells (PEMECs) has been investigated. EIS was measured during operation at various current densities of seven different PEMECs divided in five different cell types including both acidic PEMECs and alkaline PEMECs. The noise pattern differed between various types of cells and between cells of the same cell type. Integration time had no influence on the EIS noise level, whereas the AC amplitude seems to influence the EIS noise level. Other electrical noise sources influencing the EIS measurements have been studied with oscilloscope. No noise was observed at DC. A hypothesis explaining the relation between bubble formation during electrolysis and EIS noise is proposed based on the experimental findings