Influence of Solvent on Polymer Prequaternization toward Anion-Conductive Membrane Fabrication for All-Vanadium Flow Battery

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• 作者：Fengxiang Zhang ; Huamin Zhang ; Chao Qu
• 刊名：The Journal of Physical Chemistry B
• 出版年：2012
• 出版时间：August 2, 2012
• 年：2012
• 卷：116
• 期：30
• 页码：9016-9022
• 全文大小：417K
• 年卷期：v.116,no.30(August 2, 2012)
• ISSN：1520-5207

文摘

Triethylamine- (TEA-) enabled prequaternization of a polymer for nonalkaline anion-exchange membrane (AEM) fabrication is more facile and environmentally benign than the conventional trimethylamine-based postquaternization route. It is also more compatible with forming a microphase-separated membrane morphology that can facilitate ion transport. However, most studies of TEA-quaternized AEMs have reported unsatisfactory conductivities, and no examples of their application in all-vanadium flow batteries (VFBs) have been reported. In this work, we aim to address this issue and demonstrate that, by employing a favorable solvent, polysulfone can be prequaternized to a high level with TEA and further fabricated into an AEM showing good conductivity (18.2 mS cm^鈥? at room temperature) and impressive VFB performance (Coulombic efficiency above 98% and energy efficiency above 80% at 80 mA cm^鈥?). In contrast, when an unfavorable solvent is used, membrane quaternization does not occur significantly. This contrast is shown to result from the absence or presence of solvent鈥揟EA competition during quaternization, which is related to the the electron-donating or -withdrawing properties of the solvents used. Our study adds new understanding to the quaternization chemistry of AEMs and also represents the first example, to our knowledge, of a TEA-quaternized AEM yielding high VFB efficiencies.