Modelling and observing how patterning the cathode catalyst layer-electrolyte interface influences the power density of a PEMFC

Eardley, Sam Richard ORCID: 0009-0005-4659-6051 (2024). Modelling and observing how patterning the cathode catalyst layer-electrolyte interface influences the power density of a PEMFC. University of Birmingham. Ph.D.

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Abstract

To overcome the challenges faced by climate change and global warming, advances have to be made in renewable energy as we look to replace our dependence on fossil fuels as a primary energy source. One sector of renewable energy is Hydrogen Fuel Cells. Hydrogen Fuel Cells show promise, but currently can not make the world's energy demands. One way research has gone into Hydrogen Fuel Cells is through patterning the cathode-electrolyte interface of Polymer Exchange Membrane Fuel Cells (PEMFCs) to increase the active surface area of the interface, in an attempt to increase the amount of Oxygen Reduction at the interface.
In this PhD thesis, based on previous results achieved in research of patterned membranes in PEMFCs, the aim is to show that increasing the active surface area of the cathode-electrolyte interface via patterning can result in an improvement in power density output. Improving the power density is beneficial because it means more energy can be more quickly drawn from a fuel cell stack, making it easier to meet higher energy demands when required. Alternatively, the presence of a patterned interface, can allow for less platinum usage within the catalyst layers, reducing production costs, improving the power output to cost ratio.
Rather than building individual rigs for each patterned interface, an alternative approach was used of simulating models through a LiveLink between Matlab and COMSOL Multiphysics, allowing multiple simulations to be run consecutively. The advantage of this is the time saved from running multiple models in quick succession in the same time it would take for very few experiments rigs to be built and run.
A variation in parameter will be used to generate an array of models with patterned interfaces differing in height and frequency of peaks, whilst making sure to maintain a constant volume of the catalyst layer and membrane, to ensure all results are a direct consequence of the patterned interface. It has been shown that increasing surface area has a positive influence on PEMFC performance. However, given it has also been shown that the patterned interfaces can help with water management at the cathode-electrolyte interface, multiple geometries will be generated and compared with one another. This is important, because finding an optimal geometry via simulations saves time, and can be immediately applied to real life experiments in the aim of obtaining improvements in power performance.
Lastly, roughness will be applied to the surface of the interfaces. This will provide a more realistic model, as opposed to having perfectly smooth interfaces. If it can be shown that the application of roughness has little impact on the power performance, it can be assumed that the models consisting of smooth interfaces are accurate to practical experiments.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):