Characterization of Commercial Gas Diffusion Layers (GDL) by Liquid Extrusion Porometry (LEP) and Gas Liquid Displacement Porometry (GLDP)

Abstract

This works aims to study the porous characterization of several commercial Gas Diffusion Layers (GDL). Three carbon-based porous GDL featuring a highly rigid microstructure of interconnected pores of several manufacturers were analyzed. Gas Liquid Displacement Porometry (GLDP) and Liquid Extrusion Porometry (LEP) have been used to obtain their pore size distributions (PSD) and the mean and mode pore diameters (davg and dmod), by means of a gas/liquid and extrusion porometer developed at IFTS. N-dodecane liquid has been used to completely wet the GDL’s assuring penetration of the liquid into the carbon fibrous structure. The results demonstrated the accuracy of the setup on characterizing GDL in the Particle Filtration (PF) range by GLDP and LEP, with reasonable agreements of resulting PSD and average sizes between both techniques when GLDP and LEP results are compared. Differences can be explained in terms of the high pore connectivity of these kinds of structures.

CO2 flow electrolysis – limiting impact of heat and gas evolution in the electrolyte gap on current density

“…The second operation mode, flow-through, occurs when the gas-sided overpressure towards the electrolyte exceeds the GDE's bubble point pressure (Δ p GDE = p liquid − p gas < p bubble point < 0). 49 Flow-through of CO 2 into the catholyte gap is unfavorable for many reasons. First of all, the presence of gas bubbles adds to the overall cell resistance and may cause current fluctuations.…”

Integrated Taguchi and response surface methods in geometric and parameter optimization of PEM fuel cells

“…A total of 13 factors and three levels are selected for the analysis, with the main focus being obtaining the optimal combination of the factors for a maximized fuel cell power density. The parameter selection and their ranges are obtained from previous work in literature, temperature, pressure, anode and cathode relative humidity [8], anode and cathode stoichiometry ratios [19], GDL and catalyst layer porosity [26][27], flow channel depth and width, Membrane, GDL, and catalyst layer thickness [25].…”

An improved procedure for calculating the pore size distribution of filter cloths in capillary flow porometry

“…22 However, one of the main disadvantages of capillary flow porometry is that it assumes that a porous material can be represented as a bundle of parallel cylindrical tubes with circular cross-sections. 10,20,[22][23][24][25] After all, it is widely acknowledged 18,22,23,25,26 that most filter media have a complex porous structure. Viswanathan et al 24 pointed out that this simplified representation of the porous geometry, which neglects the complexities associated with an irregular crosssection of the pores, can be a source of error in the estimated filter properties.…”

“…This technique is described and used in several technical papers 4,13–26 and has many advantages, one of which is the possibility to measure numerous characteristics of a porous material, such as the largest and mean pore sizes, the PSD, gas permeability, and the envelope surface area. This nondestructive technique does not damage the sample and thus allows the reuse of the sample several times.…”

“…22 However, one of the main disadvantages of capillary flow porometry is that it assumes that a porous material can be represented as a bundle of parallel cylindrical tubes with circular cross-sections. 10,20,22–25 After all, it is widely acknowledged 18,22,23,25,26 that most filter media have a complex porous structure. Viswanathan et al.…”