Spatial Mapping of Conductance and Electric Defects in Polymer Electrolyte Membrane Electrode Assemblies Using Lock‐In Thermography with AC Excitation

The characterization of performance and losses proton exchange membrane (PEM) anion (AEM) electrolysis cells is typically carried out by electrochemical impedance spectroscopy polarization curve measurements. With these common methods, lateral inhomogeneities, local degradation, or defects cannot be mapped. Lock-in thermography (LIT) offers the possibility mapping current flows electrical losses. It has already been used successfully for many years in microelectronics photovoltaics, among others. Conventional LIT with pulsed DC excitation does not work below reversible voltage water electrolysis. Therefore, high frequencies are to generate conductivity ion membrane. Herein, first time, method variable-frequency AC (VACE)-LIT presented. combines aspects applied a PEM electrode assembly. shown that PEMs can exhibit strongly nonhomogeneous densities, presumably resulting from contact resistances layer stack. In addition, currents flowing at low indicate electronically conductive