Temperature-dependent gas accumulation in polymer electrolyte membrane electrolyzer porous transport layers

Ch, Lee; Lee, J.K.; Zhao, Benzhong; Fahy, Kieran F.; LaManna, Jacob M.; Baltic, Elias; Hussey, Daniel S.; Jacobson, David L.; Schulz, Volker P.; Bazylak, Aimy

doi:10.1016/j.jpowsour.2019.227312

Cited by 60 publications

(37 citation statements)

References 63 publications

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“…Note that their PTL thickness is 1 mm, about 3 times higher than that used in our study, which increases the transport path length and leads to more oxygen accumulation near the catalyst layer. In the study by Lee et al., a 250-μm PTL was used in neutron radiography study ( Lee et al., 2020b ), and they observed ∼0.3 oxygen saturation near the catalyst layer, which is close to the value obtained in this study.…”

Section: Resultssupporting

confidence: 88%

Observation of Preferential Pathways for Oxygen Removal through Porous Transport Layers of Polymer Electrolyte Water Electrolyzers

et al. 2020

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Summary Understanding the relationships between porous transport layer (PTL) morphology and oxygen removal is essential to improve the polymer electrolyte water electrolyzer (PEWE) performance. Operando X-ray computed tomography and machine learning were performed on a model electrolyzer at different water flow rates and current densities to determine how these operating conditions alter oxygen transport in the PTLs. We report a direct observation of oxygen taking preferential pathways through the PTL, regardless of the water flow rate or current density (1-4 A/cm 2 ). Oxygen distribution in the PTL had a periodic behavior with period of 400 μm . A computational fluid dynamics model was used to predict oxygen distribution in the PTL showing periodic oxygen front. Observed oxygen distribution is due to low in-plane PTL tortuosity and high porosity enabling merging of oxygen bubbles in the middle of the PTL and also due to aerophobicity of the layer.

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Section: Resultssupporting

confidence: 88%

Observation of Preferential Pathways for Oxygen Removal through Porous Transport Layers of Polymer Electrolyte Water Electrolyzers

et al. 2020

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“…Further studies in this direction incorporating simulations of the pore structure obtained from µ-CT measurements and artificial irregular pore networks with different pore size gradients are already in progress and can be used as a base for the development of a grading strategy in the future. Validation of the outcomes using Ti-felt PTLs could be based on X-ray synchrotron imaging or neutron imaging [49][50][51], as well as on experimental data, such as from impedance spectroscopy [52][53][54]. Apart from the optimization of mass transfer properties, the change of the ohmic resistances for charge transfer must also be considered to achieve the optimal structural design [35].…”

Section: Upscaling To Continuum Modelmentioning

confidence: 99%

Computational Optimization of Porous Structures for Electrochemical Processes

et al. 2020

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Porous structures are naturally involved in electrochemical processes. The specific architectures of the available porous materials, as well as their physical properties, crucially affect their applications, e.g., their use in fuel cells, batteries, or electrolysers. A key point is the correlation of transport properties (mass, heat, and charges) in the spatially—and in certain cases also temporally—distributed pore structure. In this paper, we use mathematical modeling to investigate the impact of the pore structure on the distribution of wetting and non-wetting phases in porous transport layers used in water electrolysis. We present and discuss the potential of pore network models and an upscaling strategy for the simulation of the saturation of the pore space with liquid and gas, as well as the computation of the relative permeabilities and oxygen dissolution and diffusion. It is studied how a change of structure, i.e., the spatial grading of the pore size distribution and porosity, change the transport properties. Several situations are investigated, including a vertical gradient ranging from small to large pore sizes and vice versa, as well as a dual-porosity network. The simulation results indicate that the specific porous structure has a significant impact on the spatial distribution of species and their respective relative permeabilities. In more detail, it is found that the continuous increase of pore sizes from the catalyst layer side towards the water inlet interface yields the best transport properties among the investigated pore networks. This outcome could be useful for the development of grading strategies, specifically for material optimization for improved transport kinetics in water electrolyser applications and for electrochemical processes in general.

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“…22 PTLs need to be optimized to deliver their versatile characteristics. [43][44][45][46][47][48][49][50] The main functions of PTL principally consist of (1) providing an electrical connection between MEA and bipolar plates, (2) conveying the fluid by capillary action from the reservoir through microchannels to the reaction sites, (3) allowing diffusion of gaseous oxygen and hydrogen to the flow channel in a direction opposite to the water flow, and (4) maintaining uniform temperature distribution and efficient heat transport within the MEA. 22,43 The multifunctional PTLs can be developed and optimized by taking these versatile roles into consideration.…”

Section: Context and Scalementioning

confidence: 99%

Increasing the performance of an anion-exchange membrane electrolyzer operating in pure water with a nickel-based microporous layer

Razmjooei

Morawietz

Taghizadeh

et al. 2021

Joule

112

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It has been technologically challenging to create an anion-exchange membrane water electrolyzer (AEMWE) that can operate efficiently without liquid electrolytes, that is, in pure water. Prior improvements in AEMWE have been limited to the development of membranes and catalysts. Here, we report an alternative solution to increase the AEMWE performance from a different perspective by developing highly conductive, macroporous layers (MPLs) as multifunctional liquid/gasdiffusion layers (LGDLs).

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Temperature-dependent gas accumulation in polymer electrolyte membrane electrolyzer porous transport layers

Cited by 60 publications

References 63 publications

Observation of Preferential Pathways for Oxygen Removal through Porous Transport Layers of Polymer Electrolyte Water Electrolyzers

Observation of Preferential Pathways for Oxygen Removal through Porous Transport Layers of Polymer Electrolyte Water Electrolyzers

Computational Optimization of Porous Structures for Electrochemical Processes

Increasing the performance of an anion-exchange membrane electrolyzer operating in pure water with a nickel-based microporous layer

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