4D in situ visualization of electrode morphology changes during accelerated degradation in fuel cells by X-ray computed tomography

White, Robin; Wu, Alex; Najm, Marina; Orfino, Francesco P.; Dutta, Monica; Kjeang, Erik

doi:10.1016/j.jpowsour.2017.03.058

Cited by 81 publications

(100 citation statements)

References 35 publications

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“…Sharma and Andersen [20] attempted to quantify the ECSA degradation mechanisms during an AST of a PEMFC catalysts layer by performing on three-electrode cells. The decrease of DLC was induced by the carbon surface area loss and the oxidation of carbon-oxygen surface groups to CO/CO 2 [21,22]. However, none of previous studies specifically clarify the correlation between ECSA and DLC degradation, which applies to analyze the effect of catalyst structural parameters on performance degradation.…”

Section: Introductionmentioning

confidence: 99%

Correlation between electrochemical performance degradation and catalyst structural parameters on polymer electrolyte membrane fuel cell

Xiong

Liu

et al. 2019

Nanotechnology Reviews

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The catalysts performance degradation is a crucial issue in decay of the polymer electrolyte membrane fuel cell (PEMFC). The effect of Nafion content, dispersity of Pt nanoparticles and selected types of carbon support on the degradation of electrochemical surface area (ECSA) and double layer capacitance (DLC) were experimentally discussed by accelerated stress test (AST). The catalyst with 20wt% Nafion content exhibited better catalyst performance. i.e., the less DLC and ECSA degradation during AST. Catalysts with well Pt dispersity showed superior %ECSA (the percentage change of ECSA) retention. The heat-treated catalysts exhibited the lowest ECSA and DLC degradation rate due to the larger Pt particle and high carbon corrosion resistance. Moreover, a multi-order model describing the correlation between ECSA and DLC degradation was proposed, providing a vital reference for quantitatively investigating ECSA and DLC degradation in the catalysts with different catalysts structural parameters.

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Section: Introductionmentioning

confidence: 99%

Correlation between electrochemical performance degradation and catalyst structural parameters on polymer electrolyte membrane fuel cell

Xiong

Liu

et al. 2019

Nanotechnology Reviews

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“…This methodology is often termed as 4DCT and is well suited to study various dynamic and evolutionary processes in polymer electrolyte fuel cell (PEFC) systems. Detailed images of the membrane electrode assembly (MEA) can be periodically obtained while the cell is still assembled in its operational housing as well as while it is producing current [3].…”

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confidence: 99%

Advanced Methods to Enable 4D Imaging of Polymer Electrolyte Fuel Cells by X-ray Computed Tomography

et al. 2018

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“…A unique and prevalent application of this technique is to acquire a set of topographies at different experimental stages to assess any dynamic changes and obtain 4-dimensional imaging of a system under study [ 2]. This methodology is well suited for the study of polymer electrolyte fuel cell systems where detailed imaging of the membrane electrode assembly (MEA) can be obtained while it is still assembled in its operational housing [ 3].Polymer electrolyte fuel cells (PEFCs) are comprised of layered structures, each with their own material properties, providing the functionality to convert hydrogen and air into usable electrical power, heat, and water. These layers can be separated into: flow fields, gas diffusion layers, cathode/anode catalyst layers, and membrane.…”

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confidence: 99%

mentioning

confidence: 99%

“…Recent research by our group employing a Zeiss Versa 520 XCT system with a custom device holder design has enabled the 4D in-situ visualization of the full MEA during degradation cycles [ 3,4]. Additional information that can still be gained relates to other fundamental material properties such as density and composition change, and visualizing these changes during 4D imaging.…”

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confidence: 99%

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Quantification of Material Property Changes During Electrode Degradation in Polymer Electrolyte Fuel Cells Using X-ray Computed Tomography

et al. 2017

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Recent developments in lab-based X-ray Computed Tomography (XCT) systems has provided the ability to obtain non-destructive 3-dimensional imaging in numerous research fields, such as geology, materials science, and biomedical imaging [ 1]. A unique and prevalent application of this technique is to acquire a set of topographies at different experimental stages to assess any dynamic changes and obtain 4-dimensional imaging of a system under study [ 2]. This methodology is well suited for the study of polymer electrolyte fuel cell systems where detailed imaging of the membrane electrode assembly (MEA) can be obtained while it is still assembled in its operational housing [ 3].Polymer electrolyte fuel cells (PEFCs) are comprised of layered structures, each with their own material properties, providing the functionality to convert hydrogen and air into usable electrical power, heat, and water. These layers can be separated into: flow fields, gas diffusion layers, cathode/anode catalyst layers, and membrane. XCT imaging relies directly on the physical properties of materials, such as density and elemental composition, to provide absorption contrast within an imaging field-of-view, which allows for the clear identification of the various materials within PEFCs [ 4]. During the operational lifetime of a PEFC, significant changes to material properties in each of these layers can occur as a result of the significant stresses associated with operational swings of temperature, RH, and voltage. These changes can be detrimental to performance and lifetime; thus, it is imperative that a comprehensive understanding of the degradation mechanisms and their impact on PEFC material properties is achieved; then, suitable mitigation strategies can be implemented.Previously, imaging of PEFC component degradation, particularly the cathode catalyst layer, which is vulnerable to damage during operational cycles, has primarily been limited to ex situ imaging, as well as, qualitative morphological changes [ 5,6]. Recent research by our group employing a Zeiss Versa 520 XCT system with a custom device holder design has enabled the 4D in-situ visualization of the full MEA during degradation cycles [ 3,4]. Additional information that can still be gained relates to other fundamental material properties such as density and composition change, and visualizing these changes during 4D imaging.In this work we present a novel approach using a 4D in-situ lab-based XCT imaging technique to obtain quantitative material changes that occur during an accelerated stress test of a cathode catalyst layer within an operational PEFC. Post data acquisition with image processing yields results of material property changes such as: density, platinum and ionomer loadings, crack formation and propagation, and thickness changes; highlighting the capabilities of this novel approach for lab-based XCT systems. Figure 1 shows the resultant structural changes following accelerated degradation cycling of a cathode catalyst layer where crack propagation and crack formatio...

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4D in situ visualization of electrode morphology changes during accelerated degradation in fuel cells by X-ray computed tomography

Cited by 81 publications

References 35 publications

Correlation between electrochemical performance degradation and catalyst structural parameters on polymer electrolyte membrane fuel cell

Correlation between electrochemical performance degradation and catalyst structural parameters on polymer electrolyte membrane fuel cell

Advanced Methods to Enable 4D Imaging of Polymer Electrolyte Fuel Cells by X-ray Computed Tomography

Quantification of Material Property Changes During Electrode Degradation in Polymer Electrolyte Fuel Cells Using X-ray Computed Tomography

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