Towards the gemini cation anion exchange membranes by nucleophilic substitution reaction

As a critical component of alkaline fuel cells, anion exchange membranes determine the energy efficiency, output power density and the long term stability. Recently, the anion exchange membranes with gemini-cation side chains exhibit superior ion conductivity due to their good nanophase separation. However, the costly and complicated synthesis limits their scaling up and commercialization. To address this problem, a convenient synthetic procedure under mild conditions is well developed. A tertiary amine precursor is introduced onto the polymer by the nucleophilic substitution reaction to avoid the conventional chloro/bromo-methylation. Followed by a simple Menshutkin reaction with 6-bromo-N,N,N-trimethylhexan-1-aminium bromide, the polymer electrolytes are obtained in a high yield. The resulting anion exchange membranes with high conductivity, good fuel cell performance and restricted swelling suggest the potential for the application in fuel cell devices. 作为碱性燃料电池的关键组分, 阴离子交换膜决定了其能量转化效率, 输出功率密度及长期稳定性. 最近, 带有双离子侧链的阴离子交换膜, 因其良好的微相分离能力, 表现出了优异的离子电导率. 然而, 昂贵且复杂的合成方法限制了其商业化应用. 为了解决这一问题, 本文开发了一种简单、温和的合成方法. 首先通过亲核取代反应将叔胺前驱体引入到聚合物主链上, 避免了常用的氯/溴甲基化反应. 随后与溴己基-N,N,N-三甲基铵进行简单的门秀金反应, 以高产率获得目标聚合物电解质. 所得到的阴离子交换膜表现出高的离子电导率, 良好的燃料电池性能以及有限的溶胀, 表明所提出的策略在燃料电池中具有应用前景.