【Ten Years of Rapid Development in Chemical Engineering Equipment】1537–2024: Development of Polyaromatic Quinonium Anion Exchange Membranes with High Alkaline Stability

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2024: A year of blooming flowers and joy – Happy Forum **********************【Ten Years of Progress in Chemical Engineering Equipment】Ongoing updates and summaries available; feel free to join the discussions at https://bbs.hcbbs.com/thread-3576046-1-1.html (Source: Haichuan Chemical Engineering Forum) ***************** Recently, the research team led by Professor Liming from Hubei University, with financial support from Wuhan Limo Film Technology Co., Ltd., has proposed new approaches to the production technology of anion exchange membranes. Ion exchange membranes are core components in the hydrogen energy industry. Electrolyzers or fuel cells built using anion exchange membranes allow for the avoidance of precious metal catalysts; the oxygen evolution/reduction reactions proceed rapidly. These membranes can be fluoride-free, resulting in no fluoride pollution upon disposal. Moreover, they can be integrated with variable renewable energy sources, which has attracted increasing interest from those working in the hydrogen industry. Depending on the type of cation, commercial anion exchange membranes have undergone three significant iterations over the past two decades, including those based on trimethylammonium, benzimidazole, and aromatic ** groups, which has greatly reduced the performance gap compared to high-performance proton exchange membranes. Currently, the main focus of research is on third-generation anion exchange membranes, namely the polyaromatic-based anion exchange membranes invented by Swedish scientist Jannasch in 2017. Research teams both domestically and internationally have conducted extensive studies on these membranes, and some teams are working on translating their findings into practical applications to drive industry development. Polyaryl** group anion exchange membranes perform well under conditions of low temperature and low concentration of alkaline solutions, but they lack stability in high-temperature and high-concentration alkaline environments. The main reason is that **the group is prone to degradation due to attack by hydroxide ions. Of course, low-temperature and low-concentration alkaline solutions cause less pollution; if there is a sufficiently effective and highly active catalyst available under such conditions, polyaryl**-based anion exchange membranes remain an excellent choice. The research team, in collaboration with Liming Technology, proposed an innovative approach by utilizing the quinuclidine ring to undergo polymerization reactions with aromatic hydrocarbons, thereby creating the fourth generation of anion exchange membranes: polyaromatic quinuclidinium anion exchange membranes. Thanks to the highly sterically hindered structure and electron-rich nature of the N-methylquinolinium cation, polyaromatic quinolinium anion exchange membranes exhibit excellent stability under high concentration and high temperature conditions. This addresses the key issue of poor basic stability associated with conventional anion exchange membranes, and it also significantly improves the membrane’s resistance to swelling. This time, Chinese scientists have transformed from followers to leaders in the field of anion exchange membranes, injecting strong momentum into the development of the new energy industry. To protect this achievement, Limo Film Technology filed a patent application on November 14, 2022, and has since been granted the patent (Patent grant number: ZL 2022 1 1416825.2; Publication number: CN 116693785A). The patent provides comprehensive protection; the nitrogen-containing heterocyclic polymer films comprise a range of electron-donating, highly bulky nitrogen-containing heterocyclic polymers, such as polyaromatic quinuclidinium ion-exchange membranes, polyaromatic C-methyl**yl ion-exchange membranes, and polyaromatic tropinyl ion-exchange membranes. Furthermore, the topological structures of polymers include homopolymers, copolymers, linear, and branched structures.