侧链多阳离子型氟化聚芴醚阴离子交换膜及其全钒液流电池性能

阳离子基团的分布对阴离子交换膜的微观相态和阴离子传导率有显著的影响.为开发全钒液流电池用高性能阴离子交换膜,本文通过向含有二甲胺基团的氟化聚芴醚前驱体接枝含阳离子烷基链的方式,合成了具有相似离子交换容量的一系列侧链多阳离子型氟化聚芴醚.实验结果表明,多阳离子侧链的引入能促进微观相分离的形成并提升阴离子传导率.同时,侧链...

Fluorinated poly(fluorenyl ether)s with linear multi-cationic side chains for vanadium redox flow batteries

The cationic group distribution along the polymeric backbones of anion exchange membranes(AEMs)has significant influence on their microscopic morphology and anion conductivity.To develop high-performance AEMs for vanadium redox flow batteries(VRFBs),a series of poly(fluorenyl ether)samples bearing di-and tri-quaternary ammonium side chains with similar ion exchange capacities(IECs)were synthesized by grafting cationic alkyl chains with tertiary amine-containing poly(fluorenyl ether)precursors.The experimental results indicate that the introduction of the multi-cationic side chains facilitates the formation of micro-phase-separated morphologies and enhances anion conductivity.Moreover,the number of spacer atoms between the quaternary ammonium groups on the side chains affects the water uptake of the membranes,thus complicating the relationship between the density of cationic group distribution and anion conductivity.The poly(fluorenyl ether)s with dicationic side chains and six spacing atoms(DQA-PFE-C6)showed the highest anion conductivity.A VRFB assembled with DQA-PFE-C6 exhibited a maximum power density of 239.80 mW cm^−2 at 250 mA cm^−2,which is significantly higher than a VRFB assembled with Nafion 212.Therefore,side chain engineering is an effective chemical approach to enhance the properties of AEMs for VRFB applications.