Preparation of gas diffusion electrodes using PEG/SiO2 hybrid materials and the effect of their composition on microstructure of the catalyst layer and on fuel cell performance

A multi-resolution simulation method was developed for the polymer electrolyte membrane (PEM) fuel cell simulation: a full 3D model was employed for the membrane and diffusion layer; a 1D+2D model was applied to the catalyst layer, that is, at each location of the fuel cell plate, the governing equations were integrated only in the direction perpendicular to the fuel cell plate; and a quasi-1D model with high numerical efficiency and reasonable accuracy was employed for the flow channels. The simulation accuracy was assessed in terms of the fuel cell polarization curves and membrane Ohmic overpotential. Overall, good agreements between the simulated results and the experimental data were obtained. However, at large current densities, with high relative humidity reactant inputs, the simulation under-predicted the fuel cell performance due to the single-phase assumption; the simulation slightly over-predicted the fuel cell performance for a dry cathode input, possibly due to the nonlinearity of the membrane properties in dehydration case. Further, a parameter study was performed under both fully humidified and relatively dry conditions for the parameters related to the cathode catalyst layer and the gas diffusion layer (GDL). It is found that the effects of liquid water in both the GDL and catalyst layer on the cell performance, and the accurate identification of the cathode catalyst layer parameters such as the cathodic transfer coefficient should be focused for future studies in order to further improve the model accuracy.

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Probing the influence of the gas diffusion layer on water retention in membrane electrode assemblies via electrochemical impedance spectroscopy

10.1149/osf.io/4cjaz ◽

2018 ◽

Author(s):

Foroughazam Afsahi ◽

E. Bradley Easton

Keyword(s):

Fuel Cell ◽

Electrochemical Impedance ◽

Catalyst Layer ◽

Pem Fuel Cell ◽

Gas Diffusion ◽

Cell Performance ◽

Carbon Paper ◽

Membrane Electrode ◽

Fuel Cell Performance ◽

Electrode Assemblies

The effect of the relative humidity (RH) of supplied gases on PEM fuel cell performance was monitored by electrochemical impedance spectroscopy (EIS). Two different Nafion®-based membrane electrode assemblies (MEAs) were prepared from two commercially available gas diffusion layers (GDLs) based on carbon paper and carbon cloth. By performing EIS measurements under condition where the transmission line model was applicable, both the ionic resistance in catalyst layer (RΣ) and the membrane resistance (Rmem) could be probed. The extent of this impact, however, depends on the GDL substrate properties and the electrode side to which the dry gas was fed. Overall, the carbon paper based MEA provided better fuel cell performance when the dry gas condition was applied, whereas the cloth based MEA revealed better fuel cell performance with fully saturated reactant gases. Moreover, the later one demonstrates a better capability to address the flooding issue at high current density even when symmetric dry gas arrangement (both dry fuel and oxidant gases) was studied. Variation of fuel gas RH at the anode perturb the fuel cell performance less strongly compared with the other arrangements. This implies that with the fully hydrated cathode gas water transport via back diffusion from the cathode to the anode could maintain the hydrated membrane and catalyst layer to some extent. By using this EIS methodology, the interplay of GDL properties and reactant gases RH on PEM fuel cell performance can be more clearly understood.

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Collaborative Design for Uneven Physical Structures of Multi-Layers in PEMFC

World Electric Vehicle Journal ◽

10.3390/wevj12030148 ◽

2021 ◽

Vol 12 (3) ◽

pp. 148

Author(s):

Qinwen Yang ◽

Shujun Chen ◽

Gang Xiao ◽

Lexi Li

Keyword(s):

Fuel Cell ◽

Diffusion Layer ◽

Collaborative Design ◽

Catalyst Layer ◽

Gas Diffusion Layer ◽

Membrane Electrode Assembly ◽

Gas Diffusion ◽

Cell Performance ◽

Membrane Electrode ◽

Fuel Cell Performance

A collaborative design for the uneven distributions of a flow channel, gas diffusion layer porosity and catalyst layer porosity are newly proposed to improve the utilization ratio of the membrane electrode assembly of the proton exchange membrane fuel cell. The effects of the uneven design of the rib width and of the uneven porosity parameters of the cathode and anode gas diffusion layer and catalyst layer on the fuel cell performance were studied in detail. Numerical simulations were designed and implemented for validation. The results show that the fuel cell performance could be improved through the collaborative design of uneven distributions for different layers. The rib width gradually decreasing and the porosity of the cathode gas diffusion layer and the cathode catalyst layer gradually increasing along the fluid flow direction would contribute to a better design compared to the regular even design. The new uneven design can make the fuel penetrate into the catalyst layer in time to participate in the reaction, improve the utilization rate of the membrane electrode assembly, and greatly improve the performance of the fuel cell.

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PEM Fuel Cell Models Validation and Accuracy Analysis

3rd International Conference on Fuel Cell Science, Engineering and Technology ◽

10.1115/fuelcell2005-74088 ◽

2005 ◽

Cited By ~ 1

Author(s):

Qingyun Liu ◽

Qiangu Yan ◽

Junxiao Wu

Keyword(s):

Fuel Cell ◽

Diffusion Layer ◽

Catalyst Layer ◽

Pem Fuel Cell ◽

Cell Plate ◽

Gas Diffusion ◽

Cell Performance ◽

Membrane Properties ◽

Parameter Study ◽

Fuel Cell Performance

A multi-resolution method is developed for the polymer electrolyte membrane (PEM) fuel cell simulation. A full 3D modeling is employed for membrane and diffusion layer, 1D+2D model is applied to the catalyst layer, that is, at each location of the fuel cell plate, the governing equations are integrated only in the direction perpendicular to the fuel cell plate; and a quasi-1D method with high numerical efficiency and reasonable accuracy is employed for the flow channels. The simulation accuracy was assessed in terms of fuel cell polarization curves and membrane ohmic overpotential. Overall, the agreements between simulated results and experimental data are good. However, at large current densities, when high relative humidity reactant inputs are employed, the simulation under predicts the fuel cell performance due to a single-phase assumption. The method slightly over predicts the fuel cell performance for a dry cathode input, possibly due to the nonlinearity of the membrane properties in dehydration case. Further, a parameter study was performed for a fully humidified cell and a relative dry cell. These parameters include porosity and permeability of gas diffusion layer; porosity, effective oxygen permeability, ratio of thickness of surrounding Nafion layer to exposed agglomerate area density and cathodic transfer coefficient of catalyst layer. Some insight can be obtained by examining their effects on the cell performances in order to further improve the model accuracy.

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Effect of Vibration on the Liquid Water Transport of PEM Fuel Cells

Volume 6: Emerging Technologies: Alternative Energy Systems; Energy Systems: Analysis, Thermodynamics and Sustainability ◽

10.1115/imece2009-12062 ◽

2009 ◽

Author(s):

Luis Breziner ◽

Peter Strahs ◽

Parsaoran Hutapea

Keyword(s):

Fuel Cells ◽

Fuel Cell ◽

Water Transport ◽

Liquid Water ◽

Pem Fuel Cells ◽

Gas Diffusion ◽

Cell Performance ◽

Sinusoidal Vibration ◽

Fuel Cell Performance ◽

Liquid Water Transport

The objective of this research is to analyze the effects of vibration on the performance of hydrogen PEM fuel cells. It has been reported that if the liquid water transport across the gas diffusion layer (GDL) changes, so does the overall cell performance. Since many fuel cells operate under a vibrating environment –as in the case of automotive applications, this may influence the liquid water concentration across the GDL at different current densities, affecting the overall fuel cell performance. The problem was developed in two main steps. First, the basis for an analytical model was established using current models for water transport in porous media. Then, a series of experiments were carried, monitoring the performance of the fuel cell for different parameters of oscillation. For sinusoidal vibration at 10, 20 and 50Hz (2 g of magnitude), a decrease in the fuel cell performance by 2.2%, 1.1% and 1.3% was recorded when compared to operation at no vibration respectively. For 5 g of magnitude, the fuel cell reported a drop of 5.8% at 50 Hz, whereas at 20 Hz the performance increased by 1.3%. Although more extensive experimentation is needed to identify a relationship between magnitude and frequency of vibration affecting the performance of the fuel cell as well as a throughout examination of the liquid water formation in the cathode, this study shows that sinusoidal vibration, overall, affects the performance of PEM fuel cells.

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