Inhomogeneous transport in model hydrated polymer electrolyte supported ultra-thin films

TL;DR

This study uses molecular dynamics simulations to explore how the surface properties of supports influence the structure and transport in ultra-thin hydrated Nafion films, revealing significant heterogeneity affecting fuel cell performance.

Contribution

It provides new insights into the impact of support wetting properties on the structure and transport in Nafion thin-films, an area previously underexplored.

Findings

Heterogeneous transport behavior in Nafion films.

Surface wetting properties significantly influence film structure.

Implications for fuel cell efficiency and design.

Abstract

Structure of polymer electrolytes membranes, e.g., Nafion, inside fuel cell catalyst layers has significant impact on the electrochemical activity and transport phenomena that determine cell performance. In those regions, Nafion can be found as an ultra-thin film, coating the catalyst and the catalyst support surfaces. The impact of the hydrophilic/hydrophobic character of these surfaces on the structural formation of the films and, in turn, on transport properties, has not been sufficiently explored yet. Here, we report about classical Molecular Dynamics simulations of hydrated Nafion thin-films in contact with unstructured supports, characterized by their global wetting properties only. We have investigated structure and transport in different regions of the film and found evidences of strongly heterogeneous behavior. We speculate about the implications of our work on experimental and technological activity.