Advanced anion-selective membranes with pendant quaternary ammonium for neutral aqueous supporting redox flow battery

• Published in: Journal of membrane science 2022-10, Vol.659, p.120748, Article 120748
• Main Authors: Xiao, Yan, Xu, Junhui, Hu, Lei, Wang, Hui, Gao, Li, Peng, Shiqi, Di, Mengting, Sun, Xiaojun, Liu, Jie, Yan, Xiaoming, Chen, Liuping, He, Gaohong
• Format: Article
• Language: English
• Subjects: Anion-selective membrane; Chemical stability; Cl− conductivity; Neutral aqueous organic redox flow battery
• ISSN: 0376-7388; 1873-3123
• DOI: 10.1016/j.memsci.2022.120748

Neutral aqueous organic redox flow battery (NAORFB) stands out as one of the most prospective mass energy storage options. The main limitations of large-scale storage regarding the NAORFB lie in the low Na+/Cl− conductivity of membrane in pH7 systems, which leads to a lower voltage efficiency. Herein, quaternary ammonium functionalized fluorinated poly (arylene ether) (QAFPAE-x) anion exchange membrane with hydrophilic and hydrophobic blocks was designed successfully. The results demonstrated that the grafting of quaternary ammonium and fluorine-containing block enables QAFPAE-x membrane low swelling, high Cl− conductivity, and promising chemical stability characteristics. The voltage efficiency of QAFPAE-100 membrane (93.8%–60.7%) is much higher than the AMVN membrane (88.4%–37.8%) at 20–160 mA cm−2. Furthermore, the NAORFB with the QAFPAE-100 membrane steadily runs at 60 mA cm−2 over 1500 cycles. Therefore, the ionic highway induced excellent performance of QAFPAE-100 membrane to render this material a promising candidate for practical NAORFB applications. [Display omitted] •A membrane with hydrophilic groups and hydrophobic block was designed.•The membrane has low swelling, high conductivity and chemical stability.•The membrane support over 1500 cycles of cells.