Determination of the porosity and its heterogeneity of fuel cell microporous layers by X-ray tomographic microscopy

Chen, Yen-Chun; Karageorgiou, Chrysoula; Eller, Jens; Schmidt, Thomas J.; Büchi, Félix N.

doi:10.1016/j.jpowsour.2022.231612

Cited by 23 publications

(20 citation statements)

References 55 publications

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“…A recent study investigating multiple commercial MPLs with X‐ray tomography and, confirmed that the reference GDL type used in this study (H14Cx483) from Freudenberg is homogeneous in thickness, but inhomogeneous with regards to the pore size distribution confirming our results. [ 20 ]…”

Section: Resultsmentioning

confidence: 99%

30 μm Thin Anode Gas Diffusion Layers for Optimized PEM Fuel Cell Operation at 120 °C and Low Relative Humidity

Yildirim,

Fadlullah,

Schwarz

et al. 2023

Adv Energy and Sustain Res

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Achieving higher temperature operation above 100 °C, while increasing the volumetric power density are key targets in current fuel cell development. In this work, a novel type of polyvinylidene fluoride and graphite based microporous film of only 30 μm thickness, acting as thin alternative to typical gas diffusion layers (GDLs) on the anode side of a hydrogen fuel cell is reported. Ex situ measurements (contact angle, electric conductivity, gas permeability measurements, and scanning electron microscopy (SEM)) reveal that the thin, porous layers achieve comparable chemical, electrical, and transport properties to commonly employed and significantly thicker gas diffusion layers. In‐situ fuel cell tests reveal considerable improvements, particularly in the target operation range beyond 100 °C: At 120 °C and 30% RH and 0.65 V cell voltage, the best thin anode layer enables a 51% higher current density (1342 vs 885 mA cm−2) and a 9% lower high frequency resistance (76 vs 84 mΩ cm−2) compared to a commercial state‐of‐the‐art GDL.

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Section: Resultsmentioning

confidence: 99%

30 μm Thin Anode Gas Diffusion Layers for Optimized PEM Fuel Cell Operation at 120 °C and Low Relative Humidity

Yildirim,

Fadlullah,

Schwarz

et al. 2023

Adv Energy and Sustain Res

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“…The contact angles of CL, CDL, and MPL are similar, but the different pore size is significant. The pore sizes of CL and MPL are 10 to 100 nm, and 20 to 500 nm, respectively 30,31 . For hydrophobicity ( θ contact > 90°), capillary pressure ( P C ) is proportional to θ contact and inversely proportional to pore size 32 .…”

Section: Resultsmentioning

confidence: 99%

“…The pore sizes of CL and MPL are 10 to 100 nm, and 20 to 500 nm, respectively. 30,31 For hydrophobicity (θ contact > 90 ), capillary pressure (P C ) is proportional to θ contact and inversely proportional to pore size. 32 CDL has a smaller pore (2-70 nm) and thus has higher P C than those of CL and MPL.…”

Section: Characterization Of CDLmentioning

confidence: 99%

Carbon nanotube‐deposited layer on cathodic catalyst layer in polymer electrolyte membrane fuel cell for enhanced performance in low humidity condition

Jeong

Kwon

Kim

et al. 2022

Intl J of Energy Research

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Summary An ultrathin layer composed of carbon nanotubes (CNTs) was deposited on the cathodic catalyst layer to boost performance of polymer electrolyte membrane fuel cell (PEMFC) under low to mid relative humidity (RH) conditions. The CNT‐deposited layer (CDL) was formed without modifying the PEMFC components. To investigate the behavior of water and reactants at the inner interface of the membrane electrode assembly (MEA), we characterized the morphology of the CDL (contact angle, pore size distribution, specific surface area, field emission scanning electron microscopy, and energy dispersive spectroscopy images). The CDL in PEMFCs was used as a contributor to enhance the membrane hydration. Thereby performances have been significantly enhanced. Additionally, the three‐dimensional nanostructure of the CDL expanded the active area by uniform dispersion of the reactants. The polarization curves of the conventional MEA and MEA with CDL were evaluated under diverse RH (100%, 70%, 50%, and 30% RH). In the low to mid RH conditions, the maximum power densities were increased by 29.7% (70% RH), 26.6% (50% RH), and 25.5% (30% RH) compared with the conventional MEA. Especially, the maximum power density of the MEA with CDL (0.547 W/cm2 at 70% RH) was higher than that of the conventional MEA (0.482 W/cm2 at 100% RH). Thus, MEA with CDL demonstrated excellent performance enhancement under low to mid RH conditions.

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“…A handful amount of experimental and numerical studies have been conducted to study the transport properties in MPL. X-ray tomographic microscopy has been used by Chen et al to experimentally characterize the MPL for obtaining their morphological parameters [ 11 ]. A newly advanced experimental method has been proposed to investigate the structural evolution and design optimization of the MPL [ 6 ].…”

Section: Introductionmentioning

confidence: 99%

Pore-Scale Modeling of Microporous Layer for Proton Exchange Membrane Fuel Cell: Effective Transport Properties

et al. 2023

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A microporous layer (MPL) is a transition layer with a porous material structure, located between the gas diffusion layer (GDL) and catalyst layer (CL) in a proton exchange membrane fuel cell (PEMFC). It not only significantly improves electron transfer and heat conduction in membrane electrode assembly, but also effectively manages liquid water transport to enhance the fuel cell performance. The MPL is usually coated on one side of the GDL. The fragile nature of MPL makes it challenging to characterize the effective transport properties using experimental methods. In this study, a stochastic numerical method is implemented to reconstruct the three-dimensional microstructure of an MPL consisting of carbon particles and PTFE. The reliability of the MPL reconstructed model is validated using experimental data. The relationship between the effective transport properties and the compression strain is obtained using the Pore Scale Model (PSM), while the relationship between the liquid water saturation and capillary pressure is solved by Lattice Boltzmann Method (LBM). The effective transport properties in the MPL are then imported into the two-phase flow fuel cell model. It is found that the effective transport parameters in MPL obtained by PSM and LBM can improve the accuracy of the model calculation. This study provides an effective method to reconstruct the microstructure of MPL that can generate precise MPL transport parameters for utilization in various PEMFC performance prediction models.

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Determination of the porosity and its heterogeneity of fuel cell microporous layers by X-ray tomographic microscopy

Cited by 23 publications

References 55 publications

30 μm Thin Anode Gas Diffusion Layers for Optimized PEM Fuel Cell Operation at 120 °C and Low Relative Humidity

30 μm Thin Anode Gas Diffusion Layers for Optimized PEM Fuel Cell Operation at 120 °C and Low Relative Humidity

Carbon nanotube‐deposited layer on cathodic catalyst layer in polymer electrolyte membrane fuel cell for enhanced performance in low humidity condition

Pore-Scale Modeling of Microporous Layer for Proton Exchange Membrane Fuel Cell: Effective Transport Properties

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