(346ap) All-Atom Molecular Dynamics Study for O2 Permeation in a Nafion Polyelectrolyte Membrane

Nafion, a perfluorosulfonic acid polymer, is the most widely studied polymeric electrolyte for Polymer electrolyte fuel cell (PEFC) applications due to its good mechanical properties, chemical stability, and high ionic conductivity.¹ In the cathode catalyst layer of PEFC, an 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 ionomer interferes with oxygen permeation to the catalytic surface.² Nevertheless, O₂ permeation can be increased either through higher diffusivity or higher solubility. However, these two parameters depend on porosity, tortuosity, and favorable O₂-Nafion interactions.³ In this work we use molecular dynamics simulations to investigate oxygen permeability in bulk Nafion, and how these permeabilities are affected by polymer chain length and side chain moieties. Understanding these effects will help in the design of new perfluorosulfonic acid (PFSA) membrane materials.

References:

1. Ryosuke Jinnouchi, Kenji Kudo, Naoki Kitano, Yu Morimoto. ‘Molecular Dynamics Simulations on O₂ Permeation through Nafion Ionomer on Platinum Surface’. (2016) Electrochim. Acta 188: 767-776.
2. Yuya Kurihara, Takuya Mabuchi, Takashi Tokumasu. ‘Molecular Simulation of Oxygen Permeation through Ionomer in Catalyst Layer’. (2014) ECS Trans 64: 559-565.
3. Tomonori Kawakami, Isamu Shigemoto, Nobuyuki Matubayasi. ‘Structure and permeability of ionomers studied by atomistic molecular simulation combined with the theory of solutions in the energy representation’. (2018) J. Chem. Phys. 148, 214903.