Thesis defence M.E. Cordóva Chávez: fuel cells
14 September 2017 10:00 - Location: Aula, TU Delft - By: Webredactie
Hybrid Organic- Inorganic Polymer Electrolyte Membranes for Low to Medium Temperature Fuel Cells. Promotor: Prof.dr. S.J. Picken (TNW).
Fuel Cells are one of the promising clean energy technologies, which are in consideration to replace fossil fuels. Unfortunately, several drawbacks have been identified. To further commercialise it, the membrane needs to be improved. Generally, the structural order of the inner phase of the membrane has been overseen. In our work, it is proven that is possible, to give order to these channels in the membrane, to find the optimal for proton conductivity. The migration of protons are believed to happen through the channels that are created in the material by the water and driven by the acidic side groups. These facts brought our attention to use of Inorganic fillers on the membrane matrix as a way to introduce water or acidic groups that helps with the proton mobility. Based on the properties mention before we selected the following materials for our studies: LiBPO4, FeSO4·7H2O and Detonation Nano diamonds. Finally, our proposal for a new hybrid PEM is to use sPEEK, with medium/high sulfonation, as a matrix mixed with Inorganic fillers. Because of its capacity to maintain the water above 100°C and its availability for proton’s movement, Together with the optimization of the inner channels, we found high conductivity in our hybrid sPEEK/LiBPO4 membrane. Conductivities of 0.1 S/cm at 100ºC and 80% R.H. (Nafion® reports similar values) were measured. A major advantage of this membrane relies on the fact that the production of sPEEK and LiBPO4 can be easily escalated to commercial production at a low cost. We would like to state the three main factors we found to be affecting the proton conductivity in a PEM: The order in the inner phase of the membrane, that needs to be optimized, the water in the membrane, which needs to be sufficient and the acidic groups in the polymer, that need to be able to protonate the water and make it a fast medium to move the positive charges. We propose and prove mechanisms in this research to tackle these three factors and address how to optimize them.
For access to theses by the PhD students you can have a look in TU Delft Repository, the digital storage of publications of TU Delft. Theses will be available within a few weeks after the actual thesis defence.