X-ray computed tomography of gas diffusion layers of PEM fuel cells: Segmentation of the microporous layer

Pfrang, Andreas; Didas, Stephan; Tsotridis, Georgios

doi:10.1016/j.jpowsour.2013.01.179

Cited by 32 publications

(20 citation statements)

References 16 publications

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“…When an MPL is coated onto the carbon fiber substrate, the MPL intrudes into the carbon fiber substrate [90,[94][95][96][97], therefore there is not a clear physical boundary between these layers. The The volume fraction of void space within a porous material is defined as the porosity.…”

Section: Gdl Porosity Characterization By X-ray Micro-computed Tomogrmentioning

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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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: Gdl Porosity Characterization By X-ray Micro-computed Tomogrmentioning

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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“…Using mCT, Markotter et al [19,20] have shown vivid visualizations of the water transport paths in the GDL with an in-situ PEMFC setup after ceasing the reactant flow. mCT has also been used to show the effects of the PTFE content in the GDL [21], to study the effect of compression on the GDL morphology [22,23], to identify and segment the MPL within the GDL [24], and to visualize the entire membrane electrode assembly (MEA) [25]. Kim et al [26] have used mCT to study the porosity variation of paper-based and felt-based GDLs under freeze-thaw cycles and have also provided an extensive review on the evaluation of water management using mCT [27].…”

Section: Introductionmentioning

confidence: 99%

X-ray Tomographic Analysis of Porosity Distributions in Gas Diffusion Layers of Proton Exchange Membrane Fuel Cells

Odaya

Phillips

Sharma

et al. 2015

Electrochimica Acta

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A B S T R A C TThis paper describes a method to characterize the structure of polytetrafluoroethylene (PTFE) treated gas diffusion layers (GDLs) with and without microporous layers (MPLs) using 3D X-ray micro computed tomographic (mCT) microscopy. In this work, the structure of single and dual layer GDLs is evaluated via mCT for various GDL samples (such as Toray TGP-H-060 and AvCarb EP40) loaded with different MPLs. A new method is presented for separating, or segmenting, the various phases of the GDL, i.e., void space, carbon fiber (including binder and PTFE), and MPL. Through analysis, it was found that the variation in bulk porosity and the average pore diameter of the GDLs depends highly on the GDL series manufacturing and treatment processes. Using advanced image analysis techniques, routines were developed to accurately segment the GDL fibers (including binder/PTFE) and the MPL. The percentage of the intruding MPL material into the carbon fiber paper as a function of the GDL thickness was successfully found for dual layer GDLs, with varying PTFE content and areal weight loading in the MPL. This analysis provides invaluable insight into the physical microstructure of paper-based GDLs, emphasizing the heterogeneous porosity distribution of single layer GDLs and the interaction of the MPL with the carbon fiber paper of dual layer GDLs.

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“…[43][44][45][46][47][48]51,56,61,62,[64][65][66][67]71 Using XCT for membrane analysis is more challegning given the relatively low X-ray attenuation of the polymer. Garzon et al 68 demonstrated that Pt redistribution from the electrodes into the membrane can be captured by XCT.…”

mentioning

confidence: 99%

3D Failure Analysis of Pure Mechanical and Pure Chemical Degradation in Fuel Cell Membranes

Singh

Orfino

Dutta

et al. 2017

J. Electrochem. Soc.

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Lifetime-limiting failure of fuel cell membranes is generally attributed to their chemical and/or mechanical degradation. Although both of these degradation modes occur concurrently during operational duty cycles, their uncoupled investigations can provide useful insights into their individual characteristics and consequential impacts on the overall membrane failure. X-ray computed tomography is emerging as an advantageous tool for fuel cell failure analysis due to its non-destructive and non-invasive 3D imaging capabilities at ambient conditions. In the present work, post-mortem failure analysis of pure mechanical and pure chemical membrane degradation modes is performed three-dimensionally using this technique. A uniquely comprehensive analysis afforded by this technique reveals that membrane failure is almost exclusively characterized by crack formations during mechanical degradation and by severe thinning accompanied by electrode shorting and pinhole formation during chemical degradation, respectively. Catalyst layer cracks, particularly on the cathode side, are found to interact strongly with mechanically induced membrane cracks. The conjoint effect of chemical and mechanical stressors is established as a necessary requirement for: (i) exclusive membrane crack development independent of catalyst layer cracks; and (ii) crack branching during membrane crack propagation. Overall, the membrane failure analysis improves its reliability and quantitative character with the adoption of 3D imaging. The transportation sector is a significant contributor to global greenhouse gas emissions and with ever-growing concerns around the global warming effect, research and development of novel clean energy based automotive solutions is being pursued worldwide. Hydrogen fuel cells have thus far emerged as a promising alternative to fossil fuel based internal combustion engines due to their clean, noisefree, and efficient operation.1 Polymer electrolyte membrane (PEM) fuel cells 2 are widely used in fuel cell electric vehicles (FCEVs) and supply electrical energy from the electrochemical conversion of hydrogen and oxygen (usually supplied as air) into water. In automotive applications, the fluctuating operating conditions due to vehicle dynamics, variations in loads and environmental conditions, startups and shutdowns, fuel starvation, contamination, and freeze-thaw cycles pose significant durability challenges for the PEM fuel cells. 3Understanding the specific durability problems and developing suitable solutions remains a key research focus in automotive PEM fuel cell technology research and is critical to the long-term and large-scale commercial adoption of this technology. Given the complex interplay of multiple physical phenomena that are simultaneously active in an operating PEM fuel cell, various deleterious factors affecting PEM fuel cell components can collectively lead to a gradual performance loss and eventual failure.In PEM fuel cells, the electrodes are separated by a polymeric membrane which allows selective tran...

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X-ray computed tomography of gas diffusion layers of PEM fuel cells: Segmentation of the microporous layer

Cited by 32 publications

References 16 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

X-ray Tomographic Analysis of Porosity Distributions in Gas Diffusion Layers of Proton Exchange Membrane Fuel Cells

3D Failure Analysis of Pure Mechanical and Pure Chemical Degradation in Fuel Cell Membranes

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