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

Muirhead, Daniel; Banerjee, Rupak; George, Michael G.; Gao, Nan; Shrestha, Pranay; Liu, Huan; Lee, Jongmin; Bazylak, Aimy

doi:10.1016/j.electacta.2018.04.050

Cited by 47 publications

(31 citation statements)

References 131 publications

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“…Overall, the findings revealed that the electrolyte distribution inside the electrode is the key element for understanding the electrochemical performance. Therefore, in situ measurements of a working silver-based GDE should be carried out revealing the electrolyte distribution, as it has been already done for carbonbased GDE used in fuel cells [29]. These measurements are presently carried out in our research groups and will be reported in a forthcoming paper.…”

Section: Resultsmentioning

confidence: 95%

Influence of binder content in silver-based gas diffusion electrodes on pore system and electrochemical performance

et al. 2019

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The influences of the polytetrafluoroethylene (PTFE) content in silver-based gas diffusion electrodes on the resulting physical properties and the electrochemical performance during oxygen reduction in concentrated sodium hydroxide electrolyte were investigated through half-cell measurements. A systematic variation of the pore system was achieved by application of different silver/PTFE ratios during the production of the gas diffusion electrodes (GDE). In all electrodes, a silver skeleton structure with relatively constant properties was formed, while the PTFE fills up part of the open pore space. The resulting structures were characterized with a variety of methods for the physical properties supported by focused ion beam milling and scanning electron microscope (FIB/SEM) tomography. It could be shown that variations in the obtained pore system strongly influence the electrochemical performance of the electrodes. Determination of the Tafel slopes revealed that this is not due to changes in the electrocatalytic activity but rather caused by variations in the electrolyte uptake. While too small amounts of PTFE (1 wt%) lead to decreased performance through electrolyte flooding, higher PTFE contents above about 5 wt% also deteriorate the electrode performance because the extent of the three-phase boundary diminishes. The decisive role of the electrolyte intrusion was confirmed by measurements at higher electrolyte pressure. While the best electrochemical performance was achieved with an electrode containing 98 wt% silver, a slightly higher PTFE content is advisable to prevent breakthrough of the electrolyte. Graphical abstractKeywords Oxygen reduction reaction · Gas diffusion electrode · Chlor-alkali electrolysis · Oxygen depolarized cathode · Silver

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Section: Resultsmentioning

confidence: 95%

Influence of binder content in silver-based gas diffusion electrodes on pore system and electrochemical performance

et al. 2019

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“…As the name suggests, the voltage loss in the Ohmic region is typically considered to be dominated by ionic and electronic losses. However, it has been shown that an increase in cell compression increases the mass transport resistance in the Ohmic region which leads to the accumulation of liquid water in the MEA, amplifying the voltage loss [9,65]. The radiographs presented in Figure 5 compare the galvanostatic cell performances at both compressions in the Ohmic region (j = 0.6 A cm -2 ).…”

Section: Ohmic Regionmentioning

confidence: 99%

Effect of cell compression on the water dynamics of a polymer electrolyte fuel cell using in-plane and through-plane in-operando neutron radiography

Kulkarni

Cho

Rasha

et al. 2019

Journal of Power Sources

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Water dynamics in the membrane electrode assembly (MEA) and flow channels of polymer electrolyte fuel cells (PEFCs) is governed by the complex interplay of many physical and operational factors. The chemical nature and structure of the gas diffusion layer (GDL) plays a large part in this and is affected by the extent to which is mechanically compressed. Here, X-ray computed tomography shows the effect of cell compression on the MEA, and how it differs under the land and channel regions. Multi-orientation neutron radiography reveals the effect of compression on the way in which water accumulates and is transported between land and channel and between cathode and anode. By performing neutron imaging in both the inplane and through-plane directions it is possible to determine what constitutes a given 'thickness' of water mapped across the extent of an MEA. Changing MEA compression from 25% to 35% has a significant effect on water distribution and dynamics in operational cells. The effect of compression on performance is most marked in the mass transport region and there are consequences for liquid accumulation in channels and back-diffusion of water from the cathode to the anode.

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“…Several visualization techniques have been employed to investigate the liquid water distribution in perforated GDLs such as neutron radiography [21][22][23], environmental scanning electron microscope (ESEM) [24,25] and synchrotron X-ray radiography [26][27][28][29][30]. Lu et al [21] employed high resolution neutron radiography to visualize the liquid water distribution in GDLs with laser perforation.…”

Section: Introductionmentioning

confidence: 99%

Two-phase flow and oxygen transport in the perforated gas diffusion layer of proton exchange membrane fuel cell

Niu

Bao

et al. 2019

International Journal of Heat and Mass Transfer

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Liquid water transport in perforated gas diffusion layers (GDLs) is numerically investigated using a threedimensional (3D) two-phase volume of fluid (VOF) model and a stochastic reconstruction model of GDL microstructures. Different perforation depths and diameters are investigated, in comparison with the GDL without perforation. It is found that perforation can considerably reduce the liquid water level inside a GDL. The perforation diameter (D = 100 lm) and the depth (H = 100 lm) show pronounced effect. In addition, two different perforation locations, i.e. the GDL center and the liquid water breakthrough point, are investigated. Results show that the latter perforation location works more efficiently. Moreover, the perforation perimeter wettability is studied, and it is found that a hydrophilic region around the perforation further reduces the water saturation. Finally, the oxygen transport in the partially-saturated GDL is studied using an oxygen diffusion model. Results indicate that perforation reduces the oxygen diffusion resistance in GDLs and improves the oxygen concentration at the GDL bottom up to 101% (D = 100 lm and H = 100 lm).

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

Cited by 47 publications

References 131 publications

Influence of binder content in silver-based gas diffusion electrodes on pore system and electrochemical performance

Influence of binder content in silver-based gas diffusion electrodes on pore system and electrochemical performance

Effect of cell compression on the water dynamics of a polymer electrolyte fuel cell using in-plane and through-plane in-operando neutron radiography

Two-phase flow and oxygen transport in the perforated gas diffusion layer of proton exchange membrane fuel cell

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