{"title":"High free volume crosslinked membranes constructed by stereocrosslinker for high-temperature proton-exchange membrane fuel cells","authors":"","doi":"10.1016/j.memsci.2024.123100","DOIUrl":null,"url":null,"abstract":"<div><p>The development of high-temperature proton-exchange membranes (HT-PEMs) with high phosphoric acid uptake (PU) and adequate mechanical strength presents a significant challenge. Researchers widely recognize crosslinking as an effective approach to address the conflict between mechanical strength and PU in phosphoric acid-doped membranes. Generally, crosslinked networks are constructed in an alkaline environment, limiting the scope of crosslinked membranes. Based on the Friedel–Crafts reaction, which occurs between carbocation ions and electron-rich skeletons or groups under acidic conditions, this study utilized a novel bifunctional 1,3-adamantanediol as a stereocrosslinker to construct a crosslinked network. The unique three-dimensional structure of the crosslinker resulted in a large free volume within the polymer networks during crosslinking, facilitating the formation of a continuous proton transfer network. Notably, compared with linear polybenzimidazole polymer (PBI), the crosslinked membranes exhibited significantly higher PA retention due to the presence of ultra-microporous structures. Additionally, the number of imidazole units remained unchanged due to the crosslinking site on the aromatic ring. As anticipated, the PA-doped crosslinked membranes exhibited a high conductivity of 167 mS cm<sup>−1</sup> and an excellent peak power density of 865 mW cm<sup>−2</sup> at 200 °C. Based on the generality of the crosslinking reaction with stereocrosslinkers and the expansion of the range of reaction media, this study proves a new insight into the fabrication of the high-performance HT-PEMs.</p></div>","PeriodicalId":368,"journal":{"name":"Journal of Membrane Science","volume":null,"pages":null},"PeriodicalIF":8.4000,"publicationDate":"2024-07-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Membrane Science","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S037673882400694X","RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ENGINEERING, CHEMICAL","Score":null,"Total":0}
引用次数: 0
Abstract
The development of high-temperature proton-exchange membranes (HT-PEMs) with high phosphoric acid uptake (PU) and adequate mechanical strength presents a significant challenge. Researchers widely recognize crosslinking as an effective approach to address the conflict between mechanical strength and PU in phosphoric acid-doped membranes. Generally, crosslinked networks are constructed in an alkaline environment, limiting the scope of crosslinked membranes. Based on the Friedel–Crafts reaction, which occurs between carbocation ions and electron-rich skeletons or groups under acidic conditions, this study utilized a novel bifunctional 1,3-adamantanediol as a stereocrosslinker to construct a crosslinked network. The unique three-dimensional structure of the crosslinker resulted in a large free volume within the polymer networks during crosslinking, facilitating the formation of a continuous proton transfer network. Notably, compared with linear polybenzimidazole polymer (PBI), the crosslinked membranes exhibited significantly higher PA retention due to the presence of ultra-microporous structures. Additionally, the number of imidazole units remained unchanged due to the crosslinking site on the aromatic ring. As anticipated, the PA-doped crosslinked membranes exhibited a high conductivity of 167 mS cm−1 and an excellent peak power density of 865 mW cm−2 at 200 °C. Based on the generality of the crosslinking reaction with stereocrosslinkers and the expansion of the range of reaction media, this study proves a new insight into the fabrication of the high-performance HT-PEMs.
开发具有高磷酸吸收率(PU)和足够机械强度的高温质子交换膜(HT-PEM)是一项重大挑战。研究人员普遍认为,交联是解决掺磷酸膜机械强度和 PU 之间矛盾的有效方法。一般来说,交联网络是在碱性环境中构建的,这限制了交联膜的应用范围。在酸性条件下,碳位离子与富含电子的骨架或基团之间会发生 Friedel-Crafts 反应,本研究利用新型双官能团 1,3-金刚烷二醇作为立体交联剂来构建交联网络。交联剂独特的三维结构使聚合物网络在交联过程中具有较大的自由体积,有利于形成连续的质子传递网络。值得注意的是,与线性聚苯并咪唑聚合物(PBI)相比,由于存在超微孔结构,交联膜对 PA 的截留率明显更高。此外,由于芳香环上的交联位点,咪唑单元的数量保持不变。正如预期的那样,掺杂 PA 的交联膜在 200 °C 时具有 167 mS cm-1 的高电导率和 865 mW cm-2 的出色峰值功率密度。基于立体交联剂交联反应的通用性和反应介质范围的扩大,本研究为高性能 HT-PEM 的制造提供了新的视角。
期刊介绍:
The Journal of Membrane Science is a publication that focuses on membrane systems and is aimed at academic and industrial chemists, chemical engineers, materials scientists, and membranologists. It publishes original research and reviews on various aspects of membrane transport, membrane formation/structure, fouling, module/process design, and processes/applications. The journal primarily focuses on the structure, function, and performance of non-biological membranes but also includes papers that relate to biological membranes. The Journal of Membrane Science publishes Full Text Papers, State-of-the-Art Reviews, Letters to the Editor, and Perspectives.