General aspects in the modeling of fuel cells: from conventional fuel cells to nano fuel cells

García-Salaberri, Pablo A.

doi:10.1016/b978-0-323-85727-7.00015-1

Cited by 11 publications

(6 citation statements)

References 134 publications

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“…Macroscopic continuum modeling is the most extended approach to analyzing transport at the cell/stack scale due to moderate computational cost and availability of multiphysics models in (commercial) CFD codes [26,45].…”

Section: Modelingmentioning

confidence: 99%

Effective transport properties for fuel cells: modeling and experimental characterization

García-Salaberri

Das

2023

Fuel Cells for Transportation

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Section: Modelingmentioning

confidence: 99%

Effective transport properties for fuel cells: modeling and experimental characterization

García-Salaberri

Das

2023

Fuel Cells for Transportation

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“…Polymer electrolyte membrane Fuel Cells (PEMFCs) are leading candidates to replace fossil‐fuel‐based power sources in many applications, especially in the transportation sector (light‐duty vehicles and trucks, submarines, airplanes, etc.) [1,2] . PEMFCs offer a higher efficiency than internal combustion engines, low noise (no moving parts), scalability and long range [3] .…”

Section: Introductionmentioning

confidence: 99%

Examining Invasion‐Percolation Across the Cathode Layered Assembly in Polymer Electrolyte Membrane Fuel Cells: Oxygen Resistance, Wettability and Cracks

García‐Salaberri

2024

ChemElectroChem

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Efficient evacuation of water generated by oxygen reduction reaction is necessary to increase catalyst utilization in polymer electrolyte membrane Fuel Cells. However, analysis of two‐phase transport is challenged by the wide range of pore sizes present in the membrane electrode assembly (MEA), varying from 10–100 nm in the catalyst layer (CL), 10–1000 nm in the microporous layer (MPL) and 10 μm in the gas diffusion layer (GDL). In this work, a novel multiscale invasion‐percolation model accounting for the cathode CL, MPL and GDL is presented. Saturation in the macroporous GDL is modeled through an all‐or‐nothing invasion law (empty/filled), while a macroscopic description in terms of the capillary pressure curve is adopted for the MPL and the CL. The oxygen transport resistance across the cathode MEA is quantified using the computed saturation distributions. Among other conclusions, the results show that MPL addition is crucial to avoid local flooding at the CL/GDL interface, providing localized access points to the GDL rather than massively invading interfacial macropores. However, excessive MPL hydrophobicity can cause CL flooding. Water removal from the CL can be enhanced by using a more hydrophilic MPL, a hydrophobic CL or the addition of a moderate volume fraction of cracks. Oxygen transport can be further improved by modulating the arrangement of water in the GDL with patterned wettability, provided that the number of MPL cracks is low.

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“…However, Pt loadings around L Pt = 0.4 mg Pt cm −2 are still the commercial standard, since a further reduction of the Pt loading has been difficult since then due to performance and durability issues (Kongkanand and Mathias, 2016;Nguyen et al, 2021;Tellez-Cruz et al, 2021). Losses are more important at the cathode due to the sluggish kinetics of the oxygen reduction reaction (ORR) and lower diffusivity of oxygen compared with the fast kinetics of the hydrogen oxidation reaction (HOR) and high diffusivity of hydrogen (Garcia-Salaberri, 2022). Concern about this situation has increased in the last decade as PEMFCs are reaching their commercialization stage, especially in the automotive sector, where they compete with other technologies (internal combustion engine and Li-ion battery) (Atanassov et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

“…A key issue for decreasing Pt loading (mainly at the cathode) is caused by local mass transport resistance introduced by thin ionomer films surrounding Pt nanoparticles (Weber and Kusoglu, 2014;Sánchez-Ramos et al, 2021, 2022. The local oxygen transport resistance (per unit of geometric area) is inversely proportional to the roughness factor, the ratio between the electrochemically active surface area and the cell geometric area, r f = A Pt A −1 geo .…”

Section: Introductionmentioning

confidence: 99%

On the optimal cathode catalyst layer for polymer electrolyte fuel cells: Bimodal pore size distributions with functionalized microstructures

2022

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A high advancement has been achieved in the design of proton exchange membrane fuel cells (PEMFCs) since the development of thin-film catalyst layers (CLs). However, the progress has slowed down in the last decade due to the difficulty in reducing Pt loading, especially at the cathode side, while preserving high stack performance. This situation poses a barrier to the widespread commercialization of fuel cell vehicles, where high performance and durability are needed at a reduced cost. Exploring the technology limits is necessary to adopt successful strategies that can allow the development of improved PEMFCs for the automotive industry. In this work, a numerical model of an optimized cathode CL is presented, which combines a multiscale formulation of mass and charge transport at the nanoscale (∼10nm) and at the layer scale (∼1μm). The effect of exterior oxygen and ohmic transport resistances are incorporated through mixed boundary conditions. The optimized CL features a vertically aligned geometry of equally spaced ionomer pillars, which are covered by a thin nanoporous electron-conductive shell. The interior surface of cylindrical nanopores is catalyzed with a Pt skin (atomic thickness), so that triple phase points are provided by liquid water. The results show the need to develop thin CLs with bimodal pore size distributions and functionalized microstructures to maximize the utilization of water-filled nanopores in which oxygen transport is facilitated compared with ionomer thin films. Proton transport across the CL must be assisted by low-tortuosity ionomer regions, which provide highways for proton transport. Large secondary pores are beneficial to facilitate oxygen distribution and water removal. Ultimate targets set by the U.S. Department of Energy and other governments can be achieved by an optimization of the CL microstructure with a high electrochemical surface area, a reduction of the oxygen transport resistance from the channel to the CL, and an increase of the catalyst activity (or maintaining a similar activity with Pt alloys). Carbon-free supports (e.g., polymer or metal) are preferred to avoid corrosion and enlarge durability.

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General aspects in the modeling of fuel cells: from conventional fuel cells to nano fuel cells

Cited by 11 publications

References 134 publications

Effective transport properties for fuel cells: modeling and experimental characterization

Effective transport properties for fuel cells: modeling and experimental characterization

Examining Invasion‐Percolation Across the Cathode Layered Assembly in Polymer Electrolyte Membrane Fuel Cells: Oxygen Resistance, Wettability and Cracks

On the optimal cathode catalyst layer for polymer electrolyte fuel cells: Bimodal pore size distributions with functionalized microstructures

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