Mohammed Bazaid

Advisor: Prof. Seung Soon Jang

will defend a doctoral thesis entitled,

Computational Investigation of Membrane and Catalyst Layer Design for Enhanced Proton and Oxygen Transport in Polymer Electrolyte Membrane Fuel Cells

On

Wednesday, October 29 at 11:00 a.m.

in-person in MRDC Room 3515

Committee
            Prof. Seung Soon Jang – School of Materials Science and Engineering (advisor)
            Prof. Mark Losego– School of Materials Science and Engineering
            Prof. Guoxiang (Emma) Hu– School of Materials Science and Engineering
            Prof. Shucong Li – School of Materials Science and Engineering

            Prof. Yu Huang – School of Materials Science and Engineering, UCLA

Abstract

    Polymer electrolyte membrane fuel cells (PEMFCs) rely on efficient proton and oxygen transport for optimal performance, with their functionality highly dependent on the structure and properties of the electrolyte membrane, catalyst layer, and ionomer distribution. In this study, molecular dynamics (MD) simulations are employed to investigate three critical aspects of PEMFCs: the electrolyte membrane nanophase separation, the effect of carbon surface functionalization on water morphology and oxygen permeability, and a novel catalyst layer design aimed at improving mass transport properties.

    In the first part of this work, we examine the performance of a short side chain perfluorosulfonic acid (PFSA) membrane as the electrolyte. The degree of nanophase separation between hydrophilic and hydrophobic domains is analyzed under varying temperature and hydration conditions to determine its effect on proton transport. The results provide insights into how phase segregation influences the formation of continuous proton-conducting networks, which are essential for achieving high ionic conductivity in fuel cell membranes.

    The second part of this study examines how oxygen-functionalized carbon in the catalyst layer reshapes interfacial water morphology and, in turn, impacts oxygen transport and proton conduction. Increasing surface oxygen content is hypothesized to enhance local hydrophilicity, promote water retention at the carbon–ionomer interface, and redistribute ionomer away from the surface. We quantify these changes and link them to oxygen permeability and to proton transport metrics, clarifying how surface chemistry modulates hydrophobic/hydrophilic partitioning in the catalyst layer. This mechanistic understanding helps rationalize experimentally observed performance enhancements upon carbon surface oxidation and guides future surface-engineering strategies

    In the third and final part of this study, a novel ionomer-free catalyst layer design is proposed in which the carbon surface is covalently functionalized with benzyl-sulfonate groups. These hydrophilic acid groups promote the formation of a thin, stable water layer that enables an alternative pathway for proton conduction while enhancing oxygen accessibility by eliminating ionomer coverage on catalyst sites. This design concept provides a molecular framework for reducing oxygen transport resistance and improving proton transport efficiency, offering a promising direction for high-performance fuel-cell architectures.

    This research provides fundamental insights into the nanoscale interactions governing proton and oxygen transport in PEMFCs, offering potential design strategies for next-generation fuel cell materials. By leveraging molecular simulations, we aim to inform the development of more efficient electrolyte membranes and catalyst layers that overcome key limitations in existing fuel cell technologies.