A comprehensive review on PEM water electrolysis

aLawrence Berkeley National Laboratory, Berkeley, California 94720, USA bLos Alamos National Laboratory, Los Alamos, New Mexico 87545, USA cUnited Technologies Research Center, East Hartford, Connecticut 06118, USA dSchool of Mechanical and Systems Engineering, Newcastle University, Newcastle upon Tyne NE1 7RU, United Kingdom eChemical and Biomolecular Engineering Department, University of California, Berkeley, California 94720, USA fFuel Cell Research and Development, General Motors, Pontiac, Michigan 48340, USA gBallard Power Systems, Burnaby, British Columbia V5J 5J8, Canada hFuel Cell Research Centre, Queens University, Kingston, Ontario K7L 3N6, Canada iDepartment of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA jDepartment of Mechanical Aerospace and Biomedical Engineering, University of Tennessee at Knoxville, Knoxville, Tennessee 37996, USA kDepartment of Mechanical Engineering Technology, SUNY Alfred State College, Alfred, New York 14802, USA lDepartment of Mechanical Engineering, University of Alberta, Edmonton, Alberta T6G 2G, Canada

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

Significant advances have been made in recent years discovering new electrocatalysts and developing a fundamental understanding of electrochemical CO2 reduction processes. This field has progressed to the point that efforts can now focus on translating this knowledge toward the development of practical CO2 electrolyzers, which have the potential to replace conventional petrochemical processes as a sustainable route to produce fuels and chemicals. In this Perspective, we take a critical look at the progress in incorporating electrochemical CO2 reduction catalysts into practical device architectures that operate using vapor-phase CO2 reactants, thereby overcoming intrinsic limitations of aqueous-based systems. Performance comparison is made between state-of-the-art CO2 electrolyzers and commercial H2O electrolyzers—a well-established technology that provides realistic performance targets. Beyond just higher rates, vapor-fed reactors represent new paradigms for unprecedented control of local reaction conditi...

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Gas-Diffusion Electrodes for Carbon Dioxide Reduction: A New Paradigm

CO2 reduction conducted in electrochemical cells with planar electrodes immersed in an aqueous electrolyte is severely limited by mass transport across the hydrodynamic boundary layer. This limitation can be minimized by use of vapor-fed, gas-diffusion electrodes (GDEs), enabling current densities that are almost two orders of magnitude greater at the same applied cathode overpotential than what is achievable with planar electrodes in an aqueous electrolyte. The addition of porous cathode layers, however, introduces a number of parameters that need to be tuned in order to optimize the performance of the GDE cell. In this work, we develop a multiphysics model for gas diffusion electrodes for CO2 reduction and used it to investigate the interplay between species transport and electrochemical reaction kinetics. The model demonstrates how the local environment near the catalyst layer, which is a function of the operating conditions, affects cell performance. We also examine the effects of catalyst layer hydrophobicity, loading, porosity, and electrolyte flowrate to help guide experimental design of vapor-fed CO2 reduction cells.

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Modeling gas-diffusion electrodes for CO2 reduction

Water management studies in PEM fuel cells, Part I: Fuel cell design and in situ water distributions

A parametric study of the effect of wetting and in proton exchange membrane (PFM) fuel cells morphological properties of the cathode porous transport layer (PTL), also known as the gas diffusion layer (GDL), on water transport in proton exchange membrane (PEM) fuel cells has been conducted using a two-dimensional network model that captures the two-phase capillary flow behavior. The effect of PTL wetting properties is explored by considering four contact angle values. The effect of the morphology is analyzed using six pore size distributions. These six pore size distributions are generated by varying the scale and shape parameters in Weibull probability distribution functions. Also, the effect of a microporous layer (MPL) on water transport in the PTL is considered. Inclusion of the MPL resulted in a significant increase in the percolation pressure and a reduction in the PTL water content due to the formation of a few localized fingers which serve as water conduits. When defects in the MPL were considered, the PTL water content remained low with percolation pressures reduced to values similar to a PTL without an MPL.

The Effects of Morphological and Wetting Properties of Porous Transport Layers on Water Movement in PEM Fuel Cells

Coupling continuum and pore-network models for polymer-electrolyte fuel cells

Evaporation, two phase flow, and thermal transport in porous media with application to low-temperature fuel cells

Water management remains a critical issue for polymer electrolyte fuel cell performance and durability, especially at lower temperatures and with ultrathin electrodes. To understand and explain experimental observations better, water transport in gas diffusion layers (GDLs) with macroscopically heterogeneous morphologies was simulated using a novel coupling of continuum and pore-network models. X-ray computed tomography was used to extract GDL material parameters for use in the pore-network model. The simulations were conducted to explain experimental observations associated with stacking of anode GDLs, where stacking of the anode GDLs increased the limiting current density. Through imaging, it is shown that the stacked anode GDL exhibited an interfacial region of high porosity. The coupled model shows that this morphology allowed more efficient water movement through the anode and higher temperatures at the cathode compared to the single GDL case. As a result, the cathode exhibited less flooding and hence better low temperature performance with the stacked anode GDL.

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Understanding Water Transport in Polymer Electrolyte Fuel Cells Using Coupled Continuum and Pore-Network Models

http://research.me.mtu.edu/abstracts/Allen-%20Existence%20of%20the%20phase%20drainage%20diagram%20in%20proton.pdf

Ezequiel Medici

Papers

The Effects of Morphological and Wetting Properties of Porous Transport Layers on Water Movement in PEM Fuel Cells

Coupling continuum and pore-network models for polymer-electrolyte fuel cells

Evaporation, two phase flow, and thermal transport in porous media with application to low-temperature fuel cells

Understanding Water Transport in Polymer Electrolyte Fuel Cells Using Coupled Continuum and Pore-Network Models

Existence of the phase drainage diagram in proton exchange membrane fuel cell fibrous diffusion media