In situ analysis of voltage degradation in a polymer electrolyte membrane fuel cell with a dead-ended anode

Chevalier, S.; Gao, Nan; Lee, J.; Antonacci, Patrick; Yip, Ronnie; George, Michael G.; Liu, H.; Banerjee, Rupak; Fazeli, Mohammadreza; Bazylak, Aimy

doi:10.1016/j.elecom.2015.06.009

Cited by 36 publications

(16 citation statements)

References 22 publications

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“…Recent works have improved the accuracy and reliability of this technique for PEM fuel cell visualizations by establishing methodologies for correcting beam position movement artifacts [58], calibrating the attenuation coefficient of liquid water and correcting sample movement artifacts [44], and considering photon scattering and harmonics [59]. In addition, the fast temporal resolutions possible with synchrotron X-ray radiography allow for dynamic visualizations of transient liquid water behaviour [60,61] and enable high-resolution in-situ tomography to resolve liquid water saturation in 3-D [48,52,62].…”

Section: Visualizations Of Liquid Water Saturationmentioning

confidence: 99%

“…Synchrotron X-ray radiography offers high spatial and temporal resolutions (less than 10 μm and less than 10 s, respectively) [38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56][57]. Though X-ray photons are not as sensitive as a neutron beam to the presence of liquid water, Chevalier et al [29] demonstrated that synchrotron X-ray radiography can achieve similar accuracy to neutron radiography with a high level of precision.…”

Section: Visualizations Of Liquid Water Saturationmentioning

confidence: 99%

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Liquid water saturation and oxygen transport resistance in polymer electrolyte membrane fuel cell gas diffusion layers

Muirhead

Banerjee

George

et al. 2018

Electrochimica Acta

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In this thesis, the relative humidity (RH) of the cathode reactant gas was investigated as a factor which influences gas diffusion layer (GDL) liquid water accumulation and mass transport-related efficiency losses over a range of operating current densities in a polymer electrolyte membrane (PEM) fuel cell. Limiting current measurements were used to characterize fuel cell oxygen transport resistance while simultaneous measurements of liquid water accumulation were conducted using synchrotron X-ray radiography. GDL porosity distributions were characterized with micro-computed tomography (μCT). The work presented here can be used by researchers to develop improved numerical models to predict GDL liquid water accumulation and to inform the design of next-generation GDL materials to mitigate mass transport-related efficiency losses. This work also contributes an extensive set of concurrent performance and liquid water visualization data to the PEM fuel cell field that can be used for validating multiphase transport models.iii

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Section: Visualizations Of Liquid Water Saturationmentioning

confidence: 99%

Section: Visualizations Of Liquid Water Saturationmentioning

confidence: 99%

Liquid water saturation and oxygen transport resistance in polymer electrolyte membrane fuel cell gas diffusion layers

Muirhead

Banerjee

George

et al. 2018

Electrochimica Acta

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“…The PEMFC with the asymmetric GDM pairing promotes more effective water management in flow-through mode (Section 2.1), and we postulate that this GDM selection will also enhance PEMFC performance in DEA mode and resolve voltage decay due to excessive accumulation of back-diffused liquid water from the cathode and dilution of the anode fuel concentration via N 2 crossover. During the DEA operation of a PEMFC, when air is supplied as the oxidant, water produced at the cathode back-diffuses across the membrane to the dry anode and accumulates in the anode flow channel [7][8][9][10][11][12]. This accumulation of water at the anode blocks the gas transport pathway.…”

Section: Pemfc Performance In Dead-ended Anode (Dea) Modementioning

confidence: 99%

“…Both of these failure modes can be exacerbated by improper materials selection inside the PEMFC. Liquid water generated at the cathode can back diffuse through the membrane and accumulate inside the anode gas diffusion media (GDM) and flow channels [7][8][9][10][11][12], blocking the gas transport pathway. When air is supplied as the oxidant, N 2 can diffuse through the membrane due to a pressure concentration gradient [7,[12][13][14][15], resulting in local fuel (i.e., H 2 ) starvation and performance loss.…”

Section: Introductionmentioning

confidence: 99%

Effect of GDM Pairing on PEMFC Performance in Flow-Through and Dead-Ended Anode Mode

et al. 2020

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Asymmetric gas diffusion media (GDM) pairing, which feature distinct GDM at the anode and cathode of the proton electrolyte membrane fuel cell (PEMFC), enhance water management compared to symmetric pairing of GDM (anode and cathode GDM are identical). An asymmetric pairing of Freudenberg GDM (H24C3 at anode and H23C2 at cathode) reduces ohmic resistances by up to 40% and oxygen transport resistances by 14% en route to 25% higher current density in dry gas flows. The asymmetric GDM pairing effectively hydrates the membrane electrode assembly (MEA) while minimizing liquid water saturation in the cathode compared to a commonly used symmetric GDM pairing of SGL 29BC at the anode and cathode. Superior water management observed with asymmetric GDM in flow-through mode is also realized in dead-ended anode (DEA) mode. Compared to the symmetric GDM pairing, the asymmetric GDM pairing with Freudenberg GDM increases cell voltage at all current densities, extends and stabilizes steady-state voltage behavior, slows voltage decay, and vastly reduces the frequency of anode purge events. These results support that the asymmetric Freudenberg GDM combination renders the PEMFC less prone to anode water saturation and performance loss from the anticipated increase in water back-diffusion during DEA mode operation.

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“…[2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] Radiographic images of the operating fuel cell during open circuit voltage (OCV) are termed dry-state images because we assume that excess liquid water is not present during this operating regime. For all non-zero current densities, radiographic images are termed wet-state images because of the possible appearance of additional liquid water with respect to the reference dry-state images (obtained at OCV).…”

mentioning

confidence: 99%

Considering Photon Scattering and Harmonics for Synchrotron X-ray Radiographic Imaging of Polymer Electrolyte Membrane Fuel Cells

Gao

George

Lee

et al. 2017

J. Electrochem. Soc.

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We predicted the attenuated, undesired secondary scattered, and undesired harmonic components of measured X-ray intensities from synchrotron X-ray radiographic visualizations of liquid water in an operating polymer electrolyte membrane (PEM) fuel cell. The undesired secondary scattered component of the measured intensity increased as a function of the liquid water thickness (traversed by the X-ray beam). This increase in the secondary scattered component led to a decrease in the calibrated attenuation coefficient for liquid water, decreasing the accuracy of water quantification. We recommend calibrating the attenuated coefficient with a range of water thicknesses defined by the maximum expected water thickness present in the PEM fuel cell. The undesired harmonic component of the measured intensity also increased as a function of liquid water thickness, which led to a decrease in the accuracy of the measured liquid water thickness. Operating the polymer electrolyte membrane (PEM) fuel cell at high current densities is a strategy for achieving effective catalyst utilization and decreasing the cost of power.1 However, high current density operation corresponds to high rates of water production, and excess liquid water can lead to the inhibition of reactant transport and poor overall fuel cell performance. Therefore, effective water management is an important design objective for the PEM fuel cell.Synchrotron X-ray radiography, with its high spatial and temporal resolutions, has been used as a diagnostic tool to directly visualize liquid water transport in PEM fuel cells in operando.2-21 Radiographic images of the operating fuel cell during open circuit voltage (OCV) are termed dry-state images because we assume that excess liquid water is not present during this operating regime. For all non-zero current densities, radiographic images are termed wet-state images because of the possible appearance of additional liquid water with respect to the reference dry-state images (obtained at OCV). The cumulative liquid water thickness traversed by the X-ray beam, t w [cm], is quantified for each pixel of a collected two-dimensional (2D) wet-state image using the following relationship 22 derived from the Beer-Lambert law:where μ at [cm −1 ] is the linear attenuation coefficient for a monoenergetic X-ray beam and is a function of the photon energy, and the subscript "w" identifies the material as water. Herein, the measured intensity of the X-ray beam after traversing the sample is referred to as the attenuated intensity. I m,dr y is the measured attenuated intensity of a reference dry-state image (in the absence of liquid water), and I m,wet is the measured attenuated intensity of a wet-state image.The accuracy of liquid water thickness quantities determined from Equation 1 corresponds to the accuracies of the measured attenuated * Electrochemical Society Student Member. 23 determined that the vertical position of the incident beam oscillated with a significant amplitude of 25 μm, which resulted in image artifacts. The auth...

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In situ analysis of voltage degradation in a polymer electrolyte membrane fuel cell with a dead-ended anode

Cited by 36 publications

References 22 publications

Liquid water saturation and oxygen transport resistance in polymer electrolyte membrane fuel cell gas diffusion layers

Liquid water saturation and oxygen transport resistance in polymer electrolyte membrane fuel cell gas diffusion layers

Effect of GDM Pairing on PEMFC Performance in Flow-Through and Dead-Ended Anode Mode

Considering Photon Scattering and Harmonics for Synchrotron X-ray Radiographic Imaging of Polymer Electrolyte Membrane Fuel Cells

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