This title appears in the Scientific Report :
2019
Optimizing Local Reaction Conditions in Porous Electrodes: Insights from Theory and Modelling
Optimizing Local Reaction Conditions in Porous Electrodes: Insights from Theory and Modelling
The drastic loading reduction or complete elimination of Pt-group metals from PEM-based fuel cellsand electrolysers remains a foremost priority for technology developers. A high emphasis in thisrealm is placed on developing electrocatalyst materials with high activity and stability. It is howeverno...
Saved in:
Personal Name(s): | Kadyk, Thomas |
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Eikerling, Michael (Corresponding author) / Muzaffar, Tasleem / Spooner, Jakob | |
Contributing Institute: |
IEK-13; IEK-13 |
Imprint: |
2019
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Conference: | Symposium on Insights into Gas Diffusion Electrodes: From Fundamentals to Industrial Applications, Magdeburg (Germany), 2019-09-23 - 2019-09-25 |
Document Type: |
Conference Presentation |
Research Program: |
Methods and Concepts for Material Development |
Publikationsportal JuSER |
The drastic loading reduction or complete elimination of Pt-group metals from PEM-based fuel cellsand electrolysers remains a foremost priority for technology developers. A high emphasis in thisrealm is placed on developing electrocatalyst materials with high activity and stability. It is howeverno less important to embed the catalyst material of choice within a well-designed porous compositeelectrode. The objectives of electrode design are to optimize the local reaction conditions at thedispersed catalyst in view of high and uniformly distributed electrochemical activity towards desiredreactions and comply with overall lifetime and durability requirements of cell operation. Furthermore,porous transport media must be developed to guarantee efficient reactant supply and productremoval to and from the active electrode layer. Theory and computation provide valuable tools toscrutinize the local variables of interest in this playing field, which are – for the case of an oxygenreduction electrode – proton density and oxygen concentration. Regarding the first variable, resultsof a molecular modelling study will be presented that reveal the variation in local proton density for aslab-like model of the catalyst-ionomer interface. The width of the water layer between metalsurface and ionomer skin layer and the density of charged anionic groups at the ionomer skin arevital parameters in this context. The local concentration of oxygen in the active electrode layer isdetermined by the macroscale diffusivity of oxygen, which is controlled by water distributions in activeand porous transport layers as well as flow conditions in flow field channels. A comprehensive watermanagement model is developed to handle this coupling. |