Molecular Dynamics Study of Oxygen Permeation in PFSA Ionomer on the Pt Catalyst Surface

Abstract

In polymer electrolyte membrane fuel cell (PEFC) cathode catalyst layer, PFSA ionomer with which the catalyst is covered is very important on the point of transferring protons to the catalytic surface on the cathode side. On the other hand, it is said that an ionomer interferes with oxygen permeation to the catalytic surface. The mechanism of oxygen permeation through an ionomer was not analyzed in detail because it is too small to research by experiment. Moreover molecular dynamics simulation of the catalyst layer and oxygen permeability has not yet studied. In this research, we constructed the system of ionomer on the platinum surface by using molecular dynamics study, and studied about the effect of the water content of the ionomer on the structure of the ionomer and permeability of the oxygen molecule.

Oxygen and Proton Transport in Flooded Graphene Pores with N-Dopants and Defects

“…Jinnouchi et al studied the transport properties of O 2 molecules inside a model of Nafion ionomer using force fields, where they showed that considerable permeation resistance occurs at gas/Nafion and Nafion/Pt interfaces. Previous MD simulations − with the DREIDING force field and F3C water model also predicted O 2 fluxes that were much higher than the experimentally measured O 2 permeation fluxes. , However, O 2 transport in flooded and ionomer-free micropores has not been studied extensively. The high-surface-area carbons containing these micropores can support Pt with high ORR current density even though transport paths are through water films conducting protons , …”