Impact of porous transport layer compression on hydrogen permeation in PEM water electrolysis

Stähler, Markus; Stähler, Andrea; Scheepers, Fabian; Lehnert, Werner; Stolten, Detlef

doi:10.1016/j.ijhydene.2019.12.016

Cited by 37 publications

(31 citation statements)

References 18 publications

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“…A recent study for proton-exchange-membrane electrolyzers found a similar compression effect by regulating the cathode-gasket thickness; higher compression improved performance but increased H 2 permeation from cathode to anode. 37 These results thus illustrate that changes to the cathode can influence the anode and measuring both, via a reference electrode, is useful to separate and understand the two effects allowing for informed optimization.…”

mentioning

confidence: 82%

Integrated Reference Electrodes in Anion-Exchange-Membrane Electrolyzers: Impact of Stainless-Steel Gas-Diffusion Layers and Internal Mechanical Pressure

Oener

Lindquist

et al. 2020

ACS Energy Lett.

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Alkaline-membrane electrolyzers operating in pure water might provide scalable low-cost H2 production but currently lag in performance and durability compared to commercial technologies. Typically, membrane–electrode assemblies (MEAs) are optimized in electrolyzers by changing one parameter at a time and assessing the resulting system performance via two-electrode polarization and impedance measurements. These approaches are limited in their ability to assign performance changes and durability to specific electrodes or processes. We integrate a reference electrode with the MEA to separate anode and cathode responses in both polarization and impedance measurements. We illustrate the power of the approach by showing how the fiber diameter of stainless-steel gas-diffusion layers (GDLs) affects performance solely at the anode, while changing the thickness of the cathode GDL simultaneously affects the performance of the anode and cathode due to changes in internal pressure from mechanical compression. This finding was obscured in conventional two-electrode measurements. The work thus guides both high-performance alkaline-membrane water-electrolyzer development and illustrates a useful strategy to study structure–activity relationships in the MEA.

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mentioning

confidence: 82%

Integrated Reference Electrodes in Anion-Exchange-Membrane Electrolyzers: Impact of Stainless-Steel Gas-Diffusion Layers and Internal Mechanical Pressure

Oener

Lindquist

et al. 2020

ACS Energy Lett.

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“…In addition, the occurrence of convection is also under discussion [35]. Furthermore, the cell compression appears to have an impact on the gas permeation across the membrane [38]. In this work, the effect on the gas crossover current density is described by adding a linear term with a constant, a x , to Equation 16:…”

Section: Faraday Efficiencymentioning

confidence: 99%

Improving the Efficiency of PEM Electrolyzers through Membrane-Specific Pressure Optimization

Scheepers

Stähler

et al. 2020

Energies

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Hydrogen produced in a polymer electrolyte membrane (PEM) electrolyzer must be stored under high pressure. It is discussed whether the gas should be compressed in subsequent gas compressors or by the electrolyzer. While gas compressor stages can be reduced in the case of electrochemical compression, safety problems arise for thin membranes due to the undesired permeation of hydrogen across the membrane to the oxygen side, forming an explosive gas. In this study, a PEM system is modeled to evaluate the membrane-specific total system efficiency. The optimum efficiency is given depending on the external heat requirement, permeation, cell pressure, current density, and membrane thickness. It shows that the heat requirement and hydrogen permeation dominate the maximum efficiency below 1.6 V, while, above, the cell polarization is decisive. In addition, a pressure-optimized cell operation is introduced by which the optimum cathode pressure is set as a function of current density and membrane thickness. This approach indicates that thin membranes do not provide increased safety issues compared to thick membranes. However, operating an N212-based system instead of an N117-based one can generate twice the amount of hydrogen at the same system efficiency while only one compressor stage must be added.

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“…The HER electrode morphology can essentially be kept similar to that of PEMFC anodes (where H 2 oxidation occurs). Pt-based catalysts supported on high surface area carbon in contact with a conventional gas diffusion layer (GDL) encompassing a microporous layer (mixture of high surface area carbon and PTFE binder) is appropriate, 241,242 Possible current leaks between the inlets/outlets of electrolyte, feeding the cells in parallel (high potential differences applied to the same channel) Larger current intensity, resulting in more expensive electrical transformer/rectifier Risk of contact failure between two neighbouring anodes/cathodes and further refinements are possible (fluorinated carbons improve the performance 243 ). On the OER side, the issue is more complex, because carbon is not stable; hence, titanium-based PTL are usually employed as the porous current collector.…”

Section: Overview Of Electrolyser Technologiesmentioning

confidence: 99%

Water electrolysis: from textbook knowledge to the latest scientific strategies and industrial developments

et al. 2022

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Impact of porous transport layer compression on hydrogen permeation in PEM water electrolysis

Cited by 37 publications

References 18 publications

Integrated Reference Electrodes in Anion-Exchange-Membrane Electrolyzers: Impact of Stainless-Steel Gas-Diffusion Layers and Internal Mechanical Pressure

Integrated Reference Electrodes in Anion-Exchange-Membrane Electrolyzers: Impact of Stainless-Steel Gas-Diffusion Layers and Internal Mechanical Pressure

Improving the Efficiency of PEM Electrolyzers through Membrane-Specific Pressure Optimization

Water electrolysis: from textbook knowledge to the latest scientific strategies and industrial developments

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