摘要
A burgeoning hydrogen technology utilizing anion exchange membranes(AEMs)has attracted increasing interest owing to its potential for cost-effective commercial values.Nonetheless,there are still challenges pertaining to conductivity and persistent stability.Herein,an innovative approach has been introduced to enhance the alkaline resistance and conductivity of AEMs viaπ-πinteractions.The synergisticπ-stacking networks in the polymer backbone induce long-range cation aggregation through directed self-assembly,generating ionic cluster microdomains.These nanoconfined environments elevate local hydroxide concentration,leading to the increased density of accessible ion hopping sites within the localized regions.Furthermore,the electron-donating effects of pyrene effectively reduce the electrostatic potential of theβ-H adjacent to quaternary ammonium cations,thus increasing the energy barrier for OH^(-)nucleophilic attack.The obtained AEMs demonstrate exceptional performance,exhibiting both high conductivity(160 mS/cm)and excellent alkaline stability(merely 0.35%conductivity degradation after 1950 h in 2 M KOH at 80℃).These good properties enable the membrane electrode assembly(MEA)to achieve the current density of 2.58 A/cm^(2) at 1.8 V,while maintaining stable operation for over 700 h in durability testing.
由于具有良好的商业前景,基于阴离子交换膜(AEMs)的新兴制氢技术引起了越来越多的关注.然而,其在离子电导率和耐久性方面仍存在挑战.本文介绍了一种新型的方法,通过π-π相互作用来增强AEMs的耐碱稳定性、提高氢氧根离子电导率.AEMs中的π-堆积诱导阳离子聚集,促进微相分离形态的形成,从而提高局部离子浓度,强化离子表面跳跃位点.除此之外,芘的给电子效应可以有效降低邻近季铵离子上的β-H的静电势,达到提高OH^(-)亲核攻击反应能垒的效果.所制备的AEMs具有优异的性能,在兼具高电导率(160 mS/cm)的同时展现了优异的耐碱稳定性(在80℃的2 M KOH中老化1950 h后,电导率仅下降0.35%).在此基础上,在电解水膜电极组件测试中在1.8 V获得了2.58 A/cm^(2)的电流密度,同时在耐久性测试中保持了700小时以上的稳定运行.
基金
supported by the National Key R&D Program of China (2022YFA1504003)
the National Natural Science Foundation of China (22322811, 22278388, 223B2804, and 22438012)
the University Synergy Innovation Program of Anhui Province (GXXT-2022027)。
