Mass Transport in Gas-evolving Electrolysers

In 2023, renewable energy generation reached an all-time high, with 29% of all electricity coming from renewable sources. However, electrical energy will not be able to fully replace fossil fuels, as the intermittency of renewable sources requires additional solutions to match the energy demand. Additionally, conversion to chemical bonds is required to supply chemicals for plastics, fertilizers, steel, etc. Electrolysis – particularly water and CO2 electrolysis – offer a promising solution to these problems by converting renewable electricity into fuels and chemical building blocks. Although electrolysis processes are very promising for the energy transition, their costs are currently still too high.
This thesis focusses on the role that gas bubbles have on the performance of electrolysers: the formation of gas bubbles is inevitable in most electrolysers, since the common electrolysis products (e.g. H2, O2 or CO) have a poor solubility in water. Controlling the behaviour of gas bubbles offers a pathway to lower the cell voltage or improve the mass transport, which allows operation at higher operating current densities. This could help with decreasing the costs of electrolysers, bringing them closer to competing with fossil fuel-based processes...