Compressive behaviour of thin catalyst layers. Part I - Experimental study

Malekian, Ali; Salari, Sina; Tam, Mickey; Oldknow, Kevin; Djilali, Ned; Bahrami, Majid

doi:10.1016/j.ijhydene.2019.04.134

Cited by 10 publications

(7 citation statements)

References 33 publications

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“…An in-house tool, thickness under compression and resistance under compression (TUC_RUC), was utilized to measure the thickness and through-plane electrical conductivity in different compression pressures. This tool has been used and evaluated in previous studies. , The thickness increased by ∼100 μm for the 1 mm distance threaded GDL and 60 μm for the 4 mm one at 1500 kPa, which showed that the thickness of the modified GDL is in the range of commercial products (the gray area in Figure c, i.e., the thickness of these two commercial products are 370 μm for Toray 120 and 110 μm for Toray 030). On the other hand, electrical resistance under compression yields similar results compared to the pristine sample, even though the threads are nonconductive (Figure d).…”

Section: Resultsmentioning

confidence: 95%

Electrode-Integrated Textile-Based Sensors for In Situ Temperature and Relative Humidity Monitoring in Electrochemical Cells

et al. 2021

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Temperature and humidity measurements in electrochemical energy devices are essential for maximizing their overall performance under different operating conditions and avoiding hazardous consequences that may arise from the malfunction of these systems. Using sensors for in situ measurements of temperature and relative humidity (RH) is a promising approach for continuous monitoring and management of electrochemical power sources. Here, we report on the feasibility of using thread-based sensors for in situ measurements of temperature and RH in proton exchange membrane fuel cells (PEMFCs) as an example of electrochemical energy devices. Commodity threads are low-cost and flexible materials that hold great promise for the creation of complex three-dimensional (3D) circuits using well-established textile methods such as weaving, braiding, and embroidering. Ex situ and in situ characterization show that threads can be introduced in the gas diffusion layer (GDL) structure to inscribe water highways within the GDL with minimal impact on the GDL microstructure and transport properties. Fluorinated ethylene propylene (FEP) is coated on thread-based sensors to decouple the response to temperature and humidity; the resulting threads achieve a linear change of resistance with temperature (−0.31%/°C), while RH is monitored with a second thread coated with poly(dimethylsiloxane) (PDMS). The combination of both threads allows for minimally invasive and dynamically responsive monitoring of local temperature and RH within the electrode of PEMFCs.

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Section: Resultsmentioning

confidence: 95%

Electrode-Integrated Textile-Based Sensors for In Situ Temperature and Relative Humidity Monitoring in Electrochemical Cells

et al. 2021

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“…In the FEM model, Young's modulus (

E_{normaly}

) and Poisson's ratio of the applied MPL and CL material are determined as 30 MPa and 0.35, which are comparable to the reported values in ref. [34]. The thickness of MPL and CL is 18 and 15

μm

, respectively, and the model length is 1000

μm

, which is sufficient to capture the representative contact behavior.…”

Section: Methodsmentioning

confidence: 99%

Numerical Investigation of Compressive Stress and Wettability Effects on Fluid Transport in Polymer Electrolyte Membrane Fuel Cell Porous Layers

2022

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The performance of polymer electrolyte membrane fuel cells (PEMFCs) is greatly influenced by the residual water content generated during the cell operation. A comprehensive understanding of water management at the interfacial regions of PEMFC components is critical for elevating the efficiency of PEMFCs. Herein, the liquid transport and accumulation at the interfacial region of 2D microporous layer (MPL) and catalyst layer (CL) are investigated numerically, considering the effects of compression stress, porosity, and wettability. The numerical scheme is assembled by finite element method (for interfacial contact mechanics) and lattice Boltzmann method (for multiphase flow and permeability calculation). Different levels of compression stress derived from fuel cell assembly pressure are applied on the MPL/CL components, which consequently lead to variations in the pore size distribution and porosity change of the MPL/CL. The results highlight the importance of considering porosity change in the compression process, where increasing compression stress significantly decreases the liquid saturation in the MPL and interfacial gap region. Additionally, strong hydrophobicity can alleviate the heterogeneity of liquid accumulation at the MPL/CL interfacial region. The liquid and gas relative permeability are also investigated to assess the liquid drainage and fuel supply efficiency with different compression stress.

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“…Over the past few years, intensive studies have been performed on GDLs as a correlation between the compressibility and performance with various characterization techniques. The aforementioned research includes the study of GDL electrophysical properties, mass-transport limitations, durability, water transport, pressure, and physicochemical properties. − One of these studies investigated the effect of PTFE treatment and MPL coating on the electrical conductivity of the GDL . Another study used mercury porosimetry to determine the influence of the hydrophobic material content of the cathode GDL on the mass-transport .…”

Section: Introductionmentioning

confidence: 99%

“…The relation between the individual characteristics and performance of the CL of MEA and GDL was studied after assembling and disassembling the FC using a nonhot pressing force . Microstructural changes, such as the plasticity and processing changes of each component, were studied using various CPs and repeatedly performing the same compression cycling …”

Section: Introductionmentioning

confidence: 99%

“…35 Microstructural changes, such as the plasticity and processing changes of each component, were studied using various CPs and repeatedly performing the same compression cycling. 36 Although considerable attention has been paid to the CP and GDL in the latest research mentioned above, unfortunately, all of these studies have been conducted only in single-sized cells. Data obtained from these cells used in the laboratory are difficult to compare with data obtained from actual field use due to differences in the reactive area.…”

Section: ■ Introductionmentioning

confidence: 99%

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Three-Dimensional Modeling and Numerical Analysis for PEM Fuel Cells

Choi

2024

ACS Sustainable Chem. Eng.

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This study aims to obtain an effective method in terms of compressive pressure to reduce the performance loss in cells with increased reaction area. The performance curve and compression pressure distribution confirmed that the performance loss increased as the reaction area increased. Therefore, the gasket thickness was adjusted to resolve this issue. By adjusting the gasket thickness, the performance loss through compression pressure could be relatively alleviated. Each ratio of activation loss (η act ), ohmic loss (η ohmic ), and mass transport loss (η mass transport ) was compared and analyzed in detail. When optimal performance was observed in the 25 and 50 cm 2 cells, a pressure range of 17.4−20.2 kPa/cm 2 was determined by investigating the internal pressure per unit area. Based on these results, the modeling of bilinear equations was established, and using this model, the range of internal compression pressure values for optimal performance in a cell with a reaction area over 50 cm 2 could be derived. This model will help determine the optimal value of the internal compression pressure to obtain high-performance, large-area cells that can be used in real life beyond the laboratory scale.

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Compressive behaviour of thin catalyst layers. Part I - Experimental study

Cited by 10 publications

References 33 publications

Electrode-Integrated Textile-Based Sensors for In Situ Temperature and Relative Humidity Monitoring in Electrochemical Cells

Electrode-Integrated Textile-Based Sensors for In Situ Temperature and Relative Humidity Monitoring in Electrochemical Cells

Numerical Investigation of Compressive Stress and Wettability Effects on Fluid Transport in Polymer Electrolyte Membrane Fuel Cell Porous Layers

Three-Dimensional Modeling and Numerical Analysis for PEM Fuel Cells

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