Nano-morphology of a polymer electrolyte fuel cell catalyst layer—imaging, reconstruction and analysis

Thiele, Simon; Zengerle, Roland; Ziegler, Christoph

doi:10.1007/s12274-011-0141-x

Cited by 99 publications

(77 citation statements)

References 45 publications

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“…[286][287][288][289][290][291][292][293][294][295] However, since it is a much more complicated structure with much smaller domain sizes and a lower amount of knowledge and imaging, such simulations and stochastic reconstructions are challenging, with limited image-based approaches being used. 294 The challenge is offset by the need since catalyst layers are the most important layers.…”

Section: Catalyst-layer Modelingmentioning

confidence: 99%

A Critical Review of Modeling Transport Phenomena in Polymer-Electrolyte Fuel Cells

Weber

Borup

Darling³

et al. 2014

J. Electrochem. Soc.

509

394

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Polymer-electrolyte fuel cells are a promising energy-conversion technology. Over the last several decades significant progress has been made in increasing their performance and durability, of which continuum-level modeling of the transport processes has played an integral part. In this review, we examine the state-of-the-art modeling approaches, with a goal of elucidating the knowledge gaps and needs going forward in the field. In particular, the focus is on multiphase flow, especially in terms of understanding interactions at interfaces, and catalyst layers with a focus on the impacts of ionomer thin-films and multiscale phenomena. Overall, we highlight where there is consensus in terms of modeling approaches as well as opportunities for further improvement and clarification, including identification of several critical areas for future research. Fuel cells may become the energy-delivery devices of the 21 st century. Although there are many types of fuel cells, polymer-electrolyte fuel cells (PEFCs) are receiving the most attention for automotive and small stationary applications. In a PEFC, fuel and oxygen are combined electrochemically. If hydrogen is used as the fuel, it oxidizes at the anode releasing proton and electrons according toThe generated protons are transported across the membrane and the electrons across the external circuit. At the cathode catalyst layer, protons and electrons recombine with oxygen to generate waterAlthough the above electrode reactions are written in single step, multiple elementary reaction pathways are possible at each electrode. During the operation of a PEFC, many interrelated and complex phenomena occur. These processes include mass and heat transfer, electrochemical reactions, and ionic and electronic transport. * Electrochemical Society Active Member. z E-mail: azweber@lbl.govOver the last several decades significant progress has been made in increasing PEFC performance and durability. Such progress has been enabled by experiments and computation at multiple scales, with the bulk of the focus being on optimizing and discovering new materials for the membrane-electrode-assembly (MEA), composed of the proton-exchange membrane (PEM), catalyst layers, and diffusionmedia (DM) backing layers. In particular, continuum modeling has been invaluable in providing understanding and insight into processes and phenomena that cannot be resolved or uncoupled through experiments. While modeling of the transport and related phenomena has progressed greatly, there are still some critical areas that need attention. These areas include modeling the catalyst layer and multiphase phenomena in the PEFC porous media.While there have been various reviews over the years of PEFC modeling 1-7 and issues, [8][9][10][11][12][13][14] as well as numerous books and book chapters, there is a need to examine critically the field in terms of what has been done and what needs to be done. This review serves that purpose with a focus on transport modeling of PEFCs. This is not meant to be an exhaustive review...

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Section: Catalyst-layer Modelingmentioning

confidence: 99%

A Critical Review of Modeling Transport Phenomena in Polymer-Electrolyte Fuel Cells

Weber

Borup

Darling³

et al. 2014

J. Electrochem. Soc.

509

394

View full text Add to dashboard Cite

show abstract

“…In the process, a FIB/SEM system was used to obtain the 3D structure of mesoporous samples (Joos et al, 2012;Porta et al, 2013;Siddique and Liu, 2010;Thiele et al, 2011;Wu et al, 2012;Zils et al, 2010). The process involves milling away a slice of the sample as thin as 10~15 nm from the side wall of a trench using FIB, and taking an SEM image of the new surface as illustrated in Figure 1.…”

Section: Fib/sem Imagingmentioning

confidence: 99%

Reliability of the spherical agglomerate models for catalyst layer in polymer electrolyte membrane fuel cells

Zhang

Ostadi

Jiang

et al. 2014

Electrochimica Acta

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“…The approach in [19] was employed to obtain the tortuosity data. An approach similar to the one shown in [32] was employed to obtain the pore size distribution for the anode geometry. As a first step, Euclidean distance from the interface to all voxel points in the pore phase was calculated using the binary matrix.…”

Section: Quantification Of Geometric Characteristicsmentioning

confidence: 99%

Geometric Characteristics of Three Dimensional Reconstructed Anode Electrodes of Lithium Ion Batteries

et al. 2014

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Abstract:The realistic three dimensional (3D) microstructure of lithium ion battery (LIB) electrode plays a key role in studying the effects of inhomogeneous microstructures on the performance of LIBs. However, the complexity of realistic microstructures imposes a significant computational cost on numerical simulation of large size samples. In this work, we used tomographic data obtained for a commercial LIB graphite electrode to evaluate the geometric characteristics of the reconstructed electrode microstructure. Based on the analysis of geometric properties, such as porosity, specific surface area, tortuosity, and pore size distribution, a representative volume element (RVE) that retains the geometric characteristics of the electrode material was obtained for further numerical studies. In this work, X-ray micro-computed tomography (CT) with 0.56 μm resolution was employed to capture the inhomogeneous porous microstructures of LIB anode electrodes. The Sigmoid transform function was employed to convert the initial raw tomographic images to binary images. Moreover, geometric characteristics of an anode electrode after 2400 cycles at the charge/discharge rate of 1 C were compared with those of a new anode electrode to investigate morphological change of the electrode. In general, the cycled electrode shows larger porosity, smaller tortuosity, and similar specific surface area compared to the new electrode. OPEN ACCESSEnergies 2014, 7 2559

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Nano-morphology of a polymer electrolyte fuel cell catalyst layer—imaging, reconstruction and analysis

Cited by 99 publications

References 45 publications

A Critical Review of Modeling Transport Phenomena in Polymer-Electrolyte Fuel Cells

A Critical Review of Modeling Transport Phenomena in Polymer-Electrolyte Fuel Cells

Reliability of the spherical agglomerate models for catalyst layer in polymer electrolyte membrane fuel cells

Geometric Characteristics of Three Dimensional Reconstructed Anode Electrodes of Lithium Ion Batteries

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