Ultra-thin, mechanically durable reinforced sulfonated poly(fluorenyl biphenyl) indole proton exchange membrane for fuel cell

• Published in: Journal of membrane science 2024-02, Vol.694, p.122393, Article 122393
• Main Authors: Thuc, Vu Dong, Kim, Dukjoon
• Format: Article
• Language: English
• Subjects: Fuel cell; Pore-filling; Proton exchange membrane; PTFE substrate; Reinforced membrane
• ISSN: 0376-7388; 1873-3123
• DOI: 10.1016/j.memsci.2023.122393

Mechanically durable and highly proton-conductive proton exchange membrane (PEM) is a crucial component for PEM fuel cell (PEMFC). Herein, we report a facile method to fabricate poly(tetrafluoroethylene) (PTFE)-reinforced composite membrane based on sulfonated poly(fluorenyl biphenyl) indole ionomer (PTFE-SPFBI). The resultant reinforced membrane exhibits an ultra-thin and dense structure, leading to a reduced swelling ratio, exceptional mechanical durability (with over 200 % elongation at break), and high chemical stability, primarily attributed to the presence of PTFE support. The ultra-thin nature of the PTFE-SPFBI membrane, coupled with its superior proton conductivity, significantly contributes to its performance in fuel cells, achieving a maximum power density of 778 mW cm−2. Notably, this reinforced membrane exhibits remarkable endurance in open-circuit voltage (OCV) test, demonstrating its ability to sustain operation for more than 500 h at 90 °C and 30 % relative humidity. Overall, our work introduces a straightforward and promising approach for the fabrication of high-performance pore-filling PEMs using hydrocarbon ionomers, emphasizing enhanced durability and proton conductivity. [Display omitted] •Reinforced SPFBI membrane was prepared with porous PTFE substrate.•Hydrocarbon SPFBI can fill PTFE pores thanks to co-solvent system of IPA-water.•PTFE-SPFBI membrane displayed low swelling and excellent mechanical properties.•In-situ OCV test showed high durability of the reinforced membrane (>500 h).