Fluorinated poly(p-triphenyl piperidine) anion exchange membranes with robust dimensional stability for fuel cells

• Published in: Journal of colloid and interface science 2023-12, Vol.651, p.404-414
• Main Authors: Yu, Ze, Gao, Wei Ting, Liu, Ying Jie, Zhang, Qiu Gen, Zhu, Ai Mei, Liu, Qing Lin
• Format: Article
• Language: English
• Subjects: Anion exchange membranes; Dimensional stability; Fluorinated groups; Hydrophilic channels; Trade-off effect
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2023.08.011

[Display omitted] Anion exchange membrane fuel cells (AEMFCs), which are more economical than proton exchange membrane fuel cells (PEMFCs), stand out in the context of the rapid development of renewable energy. Superacid-catalyzed ether-free aromatic polymers have recently received a lot of attention due to their exceptional performance, but their development has been hampered by the trade-off between the dimensional stability and ionic conductivity of anion exchange membranes (AEMs). Here, we introduced fluoroketones containing different numbers of fluorinated groups (x = 0, 3 and 6) in the main chain of p-terphenyl piperidine because of the favorable hydrophobic properties of fluorinated groups. The results show that fluorinated AEMs can enhance OH− conductivity by building more aggregated hydrophilic channels while ensuring dimensional stability. The PTF6-QAPTP AEM with more fluorinated groups has the most excellent performance at 80 °C with an OH− conductivity of 142.7 mS cm−1 and a swelling ratio (SR) of only 4.55 %. Additionally, it exhibits good alkali durability, with the OH− conductivity and quaternary ammonium (QA) cation retaining at 93.45% and 92.6%, respectively, after immersion in a 2 M NaOH solution at 80 °C for 1200 h. In addition, the power density of the PTF6-QAPTP based single cell reaches 849 mW cm−2 when the current density is 1600 mA cm−2. The PTF6-QAPTP based cell has a voltage retention of 88% after 80 h of stability testing at a constant current density of 300 mA cm−2 at 80 °C.