Isoindolinium Groups as Stable Anion Conductors for Anion-Exchange Membrane Fuel Cells and Electrolyzers.
Isoindolinium Groups as Stable Anion Conductors for Anion-Exchange Membrane Fuel Cells and Electrolyzers.
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DOI：
10.1021/acsmaterialsau.2c00002
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发表时间：
2022-05-11
期刊：
影响因子：
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通讯作者：
Diesendruck, Charles E
中科院分区：
文献类型：
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作者：
Aggarwal, Kanika;Gjineci, Nansi;Kaushansky, Alexander;Bsoul, Saja;Douglin, John C;Li, Songlin;Salam, Ihtasham;Aharonovich, Sinai;Varcoe, John R;Dekel, Dario R;Diesendruck, Charles E
阴离子交换膜（AEM）燃料电池（aemfc）和水电解槽（AEMWEs）作为替代昂贵的主流燃料电池和电解技术而受到科学界的强烈关注。然而，在aemfc和AEMWEs的高pH环境中，特别是在低水合水平下，大多数阴离子导电聚合物的分子结构会被破坏，因为氢氧阴离子与aem和离聚物中常用的季铵（QA）阳离子官能团具有很强的反应性。因此，需要新的高稳定的qa来承受这些电化学器件的强碱性环境。本研究制备了一系列不同取代基的异吲哚啉盐，并对其在干碱性条件下的稳定性进行了研究。我们发现，通过修饰异吲哚啉盐，可以添加空间位效应来改变降解动力学，并显著改善碱性稳定性，当所有芳香族位置都被取代时，达到一个数量级的改善。密度泛函理论（DFT）计算提供了支持在这些取代异吲哚盐中发现的高动力学稳定性。这是第一次对这类QAs进行研究。我们相信这些新的异吲哚基团可以成为AEMs化学设计的一个很好的选择，以克服先进电化学系统中材料稳定性的挑战。
Anion-exchange membrane (AEM) fuel cells (AEMFCs) and water electrolyzers (AEMWEs) have gained strong attention of the scientific community as an alternative to expensive mainstream fuel cell and electrolysis technologies. However, in the high pH environment of the AEMFCs and AEMWEs, especially at low hydration levels, the molecular structure of most anion-conducting polymers breaks down because of the strong reactivity of the hydroxide anions with the quaternary ammonium (QA) cation functional groups that are commonly used in the AEMs and ionomers. Therefore, new highly stable QAs are needed to withstand the strong alkaline environment of these electrochemical devices. In this study, a series of isoindolinium salts with different substituents is prepared and investigated for their stability under dry alkaline conditions. We show that by modifying isoindolinium salts, steric effects could be added to change the degradation kinetics and impart significant improvement in the alkaline stability, reaching an order of magnitude improvement when all the aromatic positions are substituted. Density functional theory (DFT) calculations are provided in support of the high kinetic stability found in these substituted isoindolinium salts. This is the first time that this class of QAs has been investigated. We believe that these novel isoindolinium groups can be a good alternative in the chemical design of AEMs to overcome material stability challenges in advanced electrochemical systems.