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Ma L, Wang T. Effects of Hydration Level and Hydrogen Bonds on Hydroxide Transport Mechanisms in Anion Exchange Membranes. CHEMSUSCHEM 2025:e2402660. [PMID: 40202021 DOI: 10.1002/cssc.202402660] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2024] [Revised: 03/17/2025] [Accepted: 04/06/2025] [Indexed: 04/10/2025]
Abstract
The transport of hydroxide in anion exchange membranes (AEMs) is generally determined by multiple factors, including hydration levels, pore morphologies, and the hydration shells of cationic groups and hydroxides. Thus, clarifying the working mechanisms benefits the proposal of strategies for enhancing the hydroxide transport, thereby enabling a rational design of high-performance AEMs. Herein, by using ReaxFF molecular dynamics (MD) simulations and RDAnalyzer, this study explores the straightforward but effective correlations for steric hindrance versus hydration shell, hydration level versus free/associated diffusion, and strong (short) hydrogen bond (SHB) versus vehicular/Grotthuss diffusion. The theoretical investigations indicate that higher steric hindrance of cationic groups results in less water in the first hydration shell of cationic groups in AEMs. Meanwhile, a higher hydration level facilitates wider hydrophilic pores of AEMs and increases the ratio of the free diffusion mechanism of hydroxides. Interestingly, this study finds a strong correlation between the number of SHBs and the Grotthuss diffusion, thereby enhancing the understanding of the high conductivity of covalent organic framework (COF)-based AEMs that contain obvious SHBs. This work provides a theoretical view for fine-tuning the free/associated and vehicular/Grotthuss transport of hydroxide in AEMs.
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Affiliation(s)
- Lunliang Ma
- Department of Chemistry, Zhejiang University, Hangzhou, 310058, China
- Center of Artificial Photosynthesis for Solar Fuels and Department of Chemistry, School of Science and Research Center for Industries of the Future, Westlake University, 600 Dunyu Road, Hangzhou, Zhejiang, 310030, China
- Institute of Natural Sciences, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou, Zhejiang, 310024, China
| | - Tao Wang
- Center of Artificial Photosynthesis for Solar Fuels and Department of Chemistry, School of Science and Research Center for Industries of the Future, Westlake University, 600 Dunyu Road, Hangzhou, Zhejiang, 310030, China
- Institute of Natural Sciences, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou, Zhejiang, 310024, China
- Division of Solar Energy Conversion and Catalysis at Westlake University, Zhejiang Baima Lake Laboratory, Hangzhou, Zhejiang, 310000, China
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Hua N, Zhang C, Zhang W, Yao X, Qian H. Development and application of ordered membrane electrode assemblies for water electrolysis. Chem Commun (Camb) 2024; 61:232-246. [PMID: 39629508 DOI: 10.1039/d4cc05300a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2024]
Abstract
With the development of hydrogen energy, there has been increasing attention toward fuel cells and water electrolysis. Among them, the zero-gap membrane electrode assembly (MEA) serves as an important triple-phase reaction site that determines the performance and efficiency of the reaction system. The development of efficient and durable MEAs plays a crucial role in the development of hydrogen energy. Consequently, a great deal of effort has been devoted to developing ordered MEAs that can effectively increase catalyst utilization, maximize triple-phase boundaries, enhance mass transfer and improve stability. The research progress of ordered MEAs in recent advances is highlighted, involving hydrogen fuel cells and low temperature water electrolysis technology. Firstly, the fundamental scientific understanding and structural characteristics of MEAs based on one-dimensional nanostructures such as nanowires, nanotubes and nanofibers are summarized. Then, the classification, preparation and development of ordered MEAs based on three-dimensional structures are summarized. Finally, this review presents current challenges and proposes future research on ordered MEAs and offers potential solutions to overcome these obstacles.
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Affiliation(s)
- Nian Hua
- Department of Chemistry, College of Sciences, Shanghai University, Shanghai 200444, China.
| | - Chuanyan Zhang
- Department of Chemistry, College of Sciences, Shanghai University, Shanghai 200444, China.
| | - Wenjie Zhang
- Department of Chemistry, College of Sciences, Shanghai University, Shanghai 200444, China.
| | - Xinyun Yao
- Department of Chemistry, College of Sciences, Shanghai University, Shanghai 200444, China.
| | - Huidong Qian
- Department of Chemistry, College of Sciences, Shanghai University, Shanghai 200444, China.
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Enhanced monovalent anion selectivity of poly(2,6-dimethyl-1,4-phenylene oxide)-based amphoteric ion exchange membranes having rough surface. J Memb Sci 2022. [DOI: 10.1016/j.memsci.2022.120911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Zhao Z, Zhang M, Du W, Xiao Y, Yang Z, Dong D, Zhang X, Fan M. Strong and Flexible High-Performance Anion Exchange Membranes with Long-Distance Interconnected Ion Transport Channels for Alkaline Fuel Cells. ACS APPLIED MATERIALS & INTERFACES 2022; 14:38132-38143. [PMID: 35971597 DOI: 10.1021/acsami.2c05872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Anion exchange membrane fuel cells (AEMFCs), which operate on a variety of green fuels, can achieve high power without emitting greenhouse gases. However, the lack of high ionic conductivity and long-term durability of anion-exchange membranes (AEMs) as their key components is a major obstacle hindering the commercial application of AEMFCs. Here, a series of homogeneous semi-interpenetrating network (semi-IPN) AEMs formed by cross-linking a copolymer of styrene (St) and 4-vinylbenzyl chloride (VBC) with branched polyethylenimine (BPEI) were designed. The pure carbon copolymer skeleton without sulfone/ether bonds accompanied by the semi-IPN endows the AEMs with excellent chemical stability. Moreover, the cross-linking effect of flexible BPEI chains is supposed to promote the "strong-flexible" mechanical properties, while the presence of multiquaternary ammonium groups can boost the formation of microphase separation, thereby enhancing the ionic conductivity of these AEMs. Consequently, the optimized (S1V1)3Q AEM exhibits an excellent hydroxide conductivity of 106 mS cm-1 at 80 °C, as well as more than 81% residual conductivity after soaking in 1 M NaOH at 60 °C for 720 h. Furthermore, the H2/O2 fuel cell assembled with (S1V1)3Q AEM delivers a peak power density of 150.2 mW cm-2 at 60 °C and 40% relative humidity. All results indicate that the approach of combining a pure carbon backbone polymer with a semi-IPN structure may be a viable strategy for fabricating AEMs that can be used in AEMFCs for long-term applications.
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Affiliation(s)
- Zhixin Zhao
- Polymer Research Institute, Sichuan University, Chengdu 610065, People's Republic of China
- State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu 610065, People's Republic of China
| | - Minghua Zhang
- College of Polymer Science and Engineering, Sichuan University, Chengdu 610065, People's Republic of China
| | - Wenhao Du
- Polymer Research Institute, Sichuan University, Chengdu 610065, People's Republic of China
- State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu 610065, People's Republic of China
| | - Yafei Xiao
- Polymer Research Institute, Sichuan University, Chengdu 610065, People's Republic of China
- State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu 610065, People's Republic of China
| | - Zhaojie Yang
- Polymer Research Institute, Sichuan University, Chengdu 610065, People's Republic of China
- State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu 610065, People's Republic of China
| | - Dawei Dong
- Polymer Research Institute, Sichuan University, Chengdu 610065, People's Republic of China
- State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu 610065, People's Republic of China
| | - Xi Zhang
- Polymer Research Institute, Sichuan University, Chengdu 610065, People's Republic of China
- State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu 610065, People's Republic of China
| | - Minmin Fan
- Polymer Research Institute, Sichuan University, Chengdu 610065, People's Republic of China
- State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu 610065, People's Republic of China
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