Fuel-Cell Catalyst-Layer Resistance via Hydrogen Limiting-Current Measurements

Schuler, Tobias; Chowdhury, Anamika; Freiberg, Anna T. S.; Sneed, Brian T.; Spingler, Franz B.; Tucker, Michael C.; More, Karren L.; Radke, Clayton J.; Weber, Adam Z.

doi:10.1149/2.0031907jes

Cited by 107 publications

(166 citation statements)

References 63 publications

Supporting

Mentioning

151

Contrasting

Unclassified

Order By: Relevance

“…Results also show that transport in the catalyst layer rather than PTL bulk dominates the mass transport overpotential based on the characteristics of a local resistance, as previously reported for polymer electrolyte fuel cells. 23,24 These findings of correlation between structural properties and cell performance lead to the following design guidelines for PTL:…”

Section: Discussionmentioning

confidence: 99%

Polymer Electrolyte Water Electrolysis: Correlating Performance and Porous Transport Layer Structure: Part II. Electrochemical Performance Analysis

Schuler

Schmidt

Büchi

2019

J. Electrochem. Soc.

Self Cite

142

206

View full text Add to dashboard Cite

In the first paper of this series the bulk and surface structural properties of Ti-fiber based porous transport layers (PTL) were characterized and described. In this second part the correlation of structure to the performance in polymer electrolyte water electrolysis cells is analyzed by determination of the three main overpotentials of ohmic, kinetics and mass transport losses. The strongest correlation between the PTL bulk transport properties and cell performance is obtained for heat transport. The current density dependent temperature gradients show good agreement with ex situ determined heat conductivity from part one. However, surface properties of the PTL materials, have a stronger influence on cell performance than the bulk properties. Catalyst layer utilization and ohmic interfacial resistances correlate with the interfacial contact areas reported in part one and performance increases with increasing contact area. This is due to a local mass transport resistance decreasing with increasing catalyst layer utilization.

show abstract

Section: Discussionmentioning

confidence: 99%

Polymer Electrolyte Water Electrolysis: Correlating Performance and Porous Transport Layer Structure: Part II. Electrochemical Performance Analysis

Schuler

Schmidt

Büchi

2019

J. Electrochem. Soc.

Self Cite

142

206

View full text Add to dashboard Cite

show abstract

“…[54,55] Hence, a simple correlation of the mass transport overpotential to geometric-normalized current densities is not suitable. [49,50] Operando imaging can be performed in future studies to better understand fluidic transport in the porous microstructures. Therefore, mass transport losses were normalized to the catalyst utilization and these data are shown in Figure 4b.…”

Section: Electrochemical Performancementioning

confidence: 99%

“…[18,[49][50][51] High catalyst utilization is therefore also essential to diminish mtx losses. Recent studies revealed that mass transport (mtx) losses are not governed by the fluid transport through the PTL bulk but by the catalyst layer interface structure.…”

mentioning

confidence: 99%

Hierarchically Structured Porous Transport Layers for Polymer Electrolyte Water Electrolysis

Schuler

Ciccone

Krentscher³

et al. 2019

Advanced Energy Materials

Self Cite

132

162

View full text Add to dashboard Cite

renewable power, from wind or solar by medium-to-long-term storage using hydrogen as the energy vector, [1,2] enabling effective decarbonisation of the energy sector. [3] PEWE converts electric power by electrochemical water splitting into storable chemical energy. [4][5][6][7] Hydrogen can be reconverted to power or used in other sectors, [8,9] such as fuel cell based mobility [10] and chemical industries. [11] To make hydrogen production with polymer electrolyte water electrolysis a technoeconomically relevant contender, capital and operational cost need to be reduced substantially. [12][13][14][15] Operational cost, which becomes the main cost driver for operation schemes with high duty ratio (≥6000 h p.a.), is governed by power prices and the hydrogen production efficiency of the PEWE plant, which in turn strongly depends on the electrochemical performance and efficiency of the PEWE cell technology employed. [16] The electrochemical efficiency is governed by the underlying electrochemical loss mechanisms of kinetic, ohmic, and mass transport losses, whereas capital cost is driven by limited power density and high noble metal catalyst loadings.Recent studies revealed that the structure of the interface between the anodic porous transport layer (PTL) and the catalyst layer (CL) is a crucial factor limiting cell efficiency. [17][18][19][20][21] Today's PEWE technology relies on porous, Ti based, transport layer materials in the form of sintered materials [17,18,[22][23][24][25] with original applications in filtration [26] or medical tissue growing. [27][28][29] The lack of PTL materials with suitable surface characteristics tailored for this application inhibits the further improvement of cell efficiency and development of PEWE technology.Kinetic losses are governed by the sluggish kinetics of the oxygen evolution reaction (OER). The related overpotential depends on intrinsic catalyst parameters, such as specific exchange current density, activation energy, and number of active catalyst sites. [30] It has been established with model experiments such as optical imaging of the PTL/CL interface [19,20,31] and correlation of in-depth electrochemical analysis with PTL surface structure [17,18] that the catalyst is only partially utilized and CL domains not directly contacted by the porous Timaterials showed no gas evolution hence no electrochemical activity. Schuler et al. [17,18] have quantified the effect, showing

show abstract

“…where is F Faraday's constant, c H 2 is the concentration of H 2 in the feed, i lim ¿¿ is the limiting current density, L is the catalyst-layer thickness, D CL is the effective reactant gas diffusivity in the catalyst-layer pores, r f is the roughness factor or the normalized electrochemically active surface area (ECSA), and R Local is the local H 2transport resistance contributed by ionomer thin film on/near Pt 41 . The first term…”

Section: Performance Of Pfmmd-co-pfsa Ionomers In Membrane Electrode mentioning

confidence: 99%

Highly Permeable Perfluorinated Sulfonic Acid Ionomers for Improved Electrochemical Devices: Insights into Structure-Property Relationships

Katzenberg¹,

Chowdhury²,

Fang³

et al. 2019

Preprint

Self Cite

View full text Add to dashboard Cite

<p>Rapid improvements in polymer-electrolyte fuel-cell (PEFC) performance have been driven by the development of commercially available ion-conducting polymers (ionomers) that are employed as membranes and catalyst binders in membrane-electrode assemblies. Commercially available ionomers are based on a perfluorinated chemistry comprised of a polytetrafluoroethylene (PTFE) matrix that imparts low gas permeability and high mechanical strength but introduces significant mass-transport losses in the electrodes. These transport losses currently limit PEFC performance, especially for low Pt loadings. In this study, we present a novel ionomer incorporating a glassy amorphous matrix based on a perfluoro(2-methylene-4-methyl-1,3-dioxolane) (PFMMD) backbone. The novel backbone chemistry induces structural changes in the ionomer, restricting ionomer domain swelling under hydration while disrupting matrix crystallinity. These structural changes slightly reduce proton conductivity while significantly improving gas permeability. The performance implications of this tradeoff are assessed, which reveal the potential for substantial performance improvement by incorporation of highly permeable ionomers as the functional catalyst binder. These results underscore the significance of tailoring material chemistry to specific device requirements, where ionomer chemistry should be rationally designed to match the local transport requirements of the device architecture.</p>

show abstract

Fuel-Cell Catalyst-Layer Resistance via Hydrogen Limiting-Current Measurements

Cited by 107 publications

References 63 publications

Polymer Electrolyte Water Electrolysis: Correlating Performance and Porous Transport Layer Structure: Part II. Electrochemical Performance Analysis

Polymer Electrolyte Water Electrolysis: Correlating Performance and Porous Transport Layer Structure: Part II. Electrochemical Performance Analysis

Hierarchically Structured Porous Transport Layers for Polymer Electrolyte Water Electrolysis

Highly Permeable Perfluorinated Sulfonic Acid Ionomers for Improved Electrochemical Devices: Insights into Structure-Property Relationships

Contact Info

Product

Resources

About