A greater understanding of the relationship between morphology and proton transfer is essential for improving next-generation perfluorosulfonic acid (PFSA) membrane fuel cells. In PFSA membranes, the separation into hydrophobic and hydrophilic domains greatly affects proton mobility in active fuel cells. Due to the amorphous nature of the polymers, the local morphology of PFSA membranes is still being actively debated. Another important factor on fuel cell performance is the presence of a catalyst layer. Previous theoretical studies have focused on examining the effect of morphology on proton transport in bulk PFSA systems. However, recent experimental work has shown that thin film membranes, such as those used in the catalyst layer, have very different properties from bulk PFSA. We therefore examine proton solvation and transport in PFSA thin film layers near the electrodes, and compare these results with those of bulk simulations. To study the proton transport in these systems, we employ multi-scale reactive molecular dynamics (MS-RMD), which allows for the reordering of bonding topology and can therefore capture the Grotthuss mechanism, but is also efficient enough to allow for calculations on relevant length and time scales.

Examining the role of morphology on proton transport in PFSA membranes

251st National Meeting (2016)

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