(Invited) Development of PFSA Ionomers for the Membrane and the Electrodes

Abstract

Perfluorosulfonic acid (PFSA) ionomer is one of the key materials used in polymer electrolyte fuel cell (PEFC). Most of the membranes used in high performance and high durability PEFC are made from PFSA ionomers. The ionomer for the membrane is required to perform well at high temperatures up to 120 °C at low relative humidity (RH). The ionomer for the electrode, besides transporting the protons to the membrane, its function in cathode of delivering the oxygen to the Pt surface is highlighted in the recent progress of high activity catalyst enabling low Pt loading. Asahi Glass Co., Ltd. (AGC) is also proposing the PFSA ionomer to be used for creating hydrophilic microporous layer (MPL) in between the gas diffusion media (GDM) and the catalyst layer to achieve better performance in low RH conditions. The monomer structures and their copolymer properties as well as their cell performance examined are presented in this paper.