Electrochemical pressure impedance spectroscopy for investigation of mass transfer in polymer electrolyte membrane fuel cells

Abstract

Mass transfer phenomena in membrane fuel cells are complex and diversified, because of the presence of complex transport pathways including porous media of very different pore sizes, and possible formation of liquid water. Electrochemical impedance spectroscopy, although allowing valuable information on ohmic, charge and mass transfer phenomena, may nevertheless appear insufficient below 1 Hz. Use of another variable i.e. back pressure as excitation variable for electrochemical pressure impedance spectroscopy is shown here a promising tool for investigations and diagnosis of fuel cells.

α‐Co(OH)2 Thin‐Layered Cactus‐Like Nanostructures Wrapped Ni3S2 Nanowires: A Robust and Potential Catalyst for Electro‐oxidation of Hydrazine

“…EIS method is a powerful tool to screen the conductive properties of the nanomaterials modified electrodes, and the changes are related with interfacial features and thus permits to realize the chemical alteration and progressions linked with the conductivity on the surface of electrode [68] . The EIS Nyquist plots obtained for all Ni foam modified electrodes were further used for evaluating electro‐oxidation of hydrazine under identical experimental conditions.…”

Polymer Electrolyte Fuel Cell Degradation Mechanisms and Their Diagnosis by Frequency Response Analysis Methods: A Review

“…These effects could include the response time of the sensor used to monitor the perturbation and output, as well as the additive effects of the fuel cell feed conditioning system which can also be affected by particular perturbations. This was shown by Shirsath et al [18], who identified that the contribution of the humidifier system affected their measurements in a certain frequency range.…”

“…The application of EPIS on PEMFCs was performed by Engebretsen et al [12] and more recently by Shirsath et al [18]. Both groups only conducted experiments under galvanostatic conditions registering the voltage responses and determining the EPIS transfer function Z V/P (see Table 3).…”

“…EPIS spectra registered at different humidity values of the gas inlet show a sensitivity of this technique to this parameter on both anode and cathode sides. Shirsath et al [18] used a setup producing back pressure perturbation through a controlled valve at the outlet. This way, they were able to obtain cleaner spectra, but the frequency range was limited up to 1 Hz.…”

“…All the mentioned methods are based on analysis of both electrical input and as well as output. Recently, several FRA methodologies based on the use of nonelectric input and/or output have been proposed for the study of PEMFCs [8][9][10][11][12][13][14][15][16][17][18]. The idea motivating their development is that by stimulating the cell through a specific nonelectrical variable instead of an electrical one, a response containing information on the dynamics of a single or few processes could be generated.…”