Poly(diallylmethylammonium) proton conducting membranes with high ionic conductivity at intermediate temperatures
Poly(diallylmethylammonium) proton conducting membranes with high ionic conductivity at intermediate temperatures
复制标题
DOI：
10.1016/j.polymer.2023.126064
复制
发表时间：
2023-06-06
期刊：
影响因子：
4.6
通讯作者：
Mecerreyes，David
中科院分区：
文献类型：
--
作者：
Gallastegui，Antonela;Foglia，Fabrizia;Mecerreyes，David
高温质子交换膜燃料电池由于其高能量效率、其上级热/水管理、CO耐受性和电极反应动力学而最近被研究。为了进一步推进这项技术，聚合物膜的组合和性能应针对中温或高温操作（>100 °C）进行改进。在这项工作中，我们提出了新的聚（二烯丙基甲基铵）质子传导膜在120 °C的高离子电导率。首先，合成了新的质子离子液体，下文称为DAMAH+X−，导致具有不同抗衡阴离子的二烯丙基甲基铵单体。通过热引发和光引发的自由基环化聚合，获得了聚（二烯丙基甲基铵X−）的自立质子聚合物膜。膜显示出良好的热稳定性（>250 °C）和机械性能，而不需要添加剂，例如（质子）离子液体、溶剂或无机电荷。着重研究了不同抗衡阴离子对膜性能的影响。作为一般趋势，来自强酸的氟化阴离子赋予高离子电导率并允许降低质子聚合物膜上的吸湿性。用中子散射（QENS和NR）方法研究了不同温度和湿度条件下质子的结构和动力学稳定性。优化的聚（二烯丙基甲基铵X−）在80 °C的不同相对湿度条件下显示出与Nafion 212相似的离子电导率值。此外，它在120 °C干燥条件下显示出1.9 × 10−3S cm− 1的高离子电导率值。
High temperature proton exchange membrane fuel cells are being lately investigated because of their high energy efficiency, their superior heat/water management, CO tolerance, and electrode reaction kinetics. To further advance this technology, the polymer membrane portfolio and performance should be improved for intermediate or high temperature operation (>100 °C). In this work we present new poly(diallylmethylammonium) proton conducting membranes with high ionic conductivity at 120 °C. First, new protic ionic liquids, hereafter called DAMAH+X−, were synthesized leading to diallylmethylammonium monomers with different counter-anions. By radical cyclopolymerization through thermal and photoinitiation mechanisms, self-standing protic polymeric membranes of poly(diallylmethylammonium X−) were obtained. Membranes showed good thermal stability (>250 °C) and mechanical properties without the need of additives such as (protic) ionic liquids, solvents or inorganic charges. Great attention was paid to understand the effect of the different counter-anions on the membrane properties. As a general trend, fluorinated anions coming from strong acids confer high ionic conductivity and allow to reduce the hygroscopic properties on the protic polymeric membranes. Proton structural and dynamical stability at different temperatures and humidification conditions were investigated by Neutron Scattering (QENS and NR). The optimized poly(diallylmethylammonium X−) shows similar ionic conductivity values than Nafion 212 under varying relative humidity conditions at 80 °C. Furthermore, it shows a high ionic conductivity value of 1.9 × 10−3S cm−1at 120 °C under dry conditions.