具有超高碱性稳定性和尺寸稳定性的聚芳烃N-甲基奎宁基阴离子交换膜

Poly(aryl N-methyl quinuclidinium) anion exchange membrane with both ultra-high alkaline stability and dimensional stability

阴离子交换膜水电解槽的阴离子交换膜成本低、无需铂族贵金属催化剂,有望取代高成本的质子交换膜水电解槽.然而,阴离子交换膜的尺寸稳定性差以及在高温、高浓度碱液中的稳定性差,阻碍了阴离子交换膜水电解槽的发展.最近,我们合成了一种具有优异碱性稳定性的聚(三苯基-N-甲基奎宁基)阴离子交换膜,为了进一步提高这种阴离子交换膜的机械强度和尺寸稳定性,在本工作中,我们添加了三氟苯乙酮来制备聚(三苯基-三氟苯乙酮-N-甲基奎宁基)阴离子交换膜.这种共聚阴离子交换膜具有超高的碱性稳定性(在80℃,10 mol L^(-1)的NaOH溶液中浸泡1600小时后OH^(-)电导率和机械强度不发生衰减),优异的尺寸稳定性(30–80℃温度下,纯水中溶胀率不超过7%;10 mol L^(-1)的NaOH溶液中溶胀率不超过2%),高氢氧根电导率(80°C时达134.5 mS cm^(-1))和高机械强度(抗拉伸强度达43.2 MPa).这种阴离子交换膜和镍合金泡沫电极组装的简易水电解槽在80°C下,2.0 V和5 mol L^(-1)的KOH水电解质中具有1780 mA cm^(-2)的优异电流密度,并且具有高耐久性.

Anion exchange membrane(AEM) water electrolyser provides a promising alternative to proton exchange membrane water electrolysis due to the relative cheap of AEM and no-need of expensive platinum group catalysts. However,the development of AEM water electrolyser is hampered by the low alkaline and dimensional stability of AEMs, especially in highly concentrated alkaline solution and at elevated temperatures. Recently we synthesized a poly(triphenyl N-methylquinuclidinium) AEM with excellent alkaline stability. To further improve the mechanical strength and dimensional stability of this kind of AEM, in this work, we added trifluoacetophenone to prepare a poly(triphenyl trifluoacetophenone N-methylquinuclidinium) membrane, which exhibits superior alkaline stability(no degradation of conductivity and mechanical strength for 1600 h in 10 mol L^(-1)NaOH at 80℃),excellent dimensional stability(swelling ratio: <7%, in pure water, 30±80℃;<2%, in 10 mol L^(-1)NaOH, 30±80℃), high OH-conductivity(134.5 mS cm^(-1)at 80℃) and high mechanical strength(tensile strength = 43.2 MPa). The assembled water electrolyser, comprising this AEM and nickel-alloy foam electrodes,exhibitsoutstandingcurrentdensity(1780 mA cm^(-2)) at 2.0 V with 5 mol L^(-1)KOH aqueous electrolyte at 80℃, and high durability when assembled with nickel foam electrodes.