Poly(arylene alkylene)s functionalized with perfluorosulfonic acid groups as proton exchange membranes for vanadium redox flow batteries

• Published in: Journal of membrane science Vol. 671; p. 121390
• Main Authors: Khataee, Amirreza, Nederstedt, Hannes, Jannasch, Patric, Lindström, Rakel Wreland
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 05.04.2023
• Subjects: Analytical Chemistry; Analytisk kemi; Chemical Engineering; Chemical Sciences; Energisystem; Energy Systems; Engineering and Technology; Environmental Engineering; Kemi; Kemiteknik; Materialkemi; Materials Chemistry; Nafion; Natural Sciences; Naturresursteknik; Naturvetenskap; Polymer Chemistry; Polymer Technologies; Polymerkemi; Polymerteknologi; Polyphenylene; Proton exchange membrane; Sulfonic acid; Teknik; Vanadium redox flow battery; Vanadium redox flow battery; Proton exchange membrane; Nafion; Sulfonic acid; Polyphenylene
• ISSN: 0376-7388; 1873-3123; 1873-3123
• DOI: 10.1016/j.memsci.2023.121390

With the aim to develop vanadium redox flow battery (VRFB) membranes beyond state of the art, we have in the present work functionalized poly(p-terphenylene)s with highly acidic perfluorosulfonic groups and investigated their performance as proton exchange membranes (PEMs). Consequently, two poly(p-terphenylene alkylene)s tethered with perfluoroalkylsulfonic acid and perfluorophenylsulfonic acid, respectively, were synthesized through superacid-mediated polyhydroxyalkylations and cast into PEMs. Compared with Nafion 212, the PEM carrying perfluorophenylsulfonic acid groups (PTPF-Phenyl-SA) was found to exhibit higher ionic conductivity and eight times lower vanadium (IV) permeation rate. The latter explains the longer self-discharge duration of the VRFB based on the PTPF-Phenyl-SA. In addition, the VRFB assembled with the PTPF-Phenyl-SA PEM exhibited a high average coulombic efficiency of 99.6% for over 100 cycles with a capacity fade of 0.24% per cycle, which was 50% lower than when Nafion 212 was used. More importantly, excellent capacity retention was achieved through electrochemical rate performance experiments at different current densities. [Display omitted] •Poly(p-terphenylene alkylene)s proton exchange membranes (PEMs) were synthesized.•The PEM tethered with perfluoroalkylsulfonic acid showed significant performance.•A balance between IEC, WU and thickness lead to high capacity retention.•No molecular changes in PEMs were recorded by NMR analysis after battery tests.