Selective ion transport through hydrated micropores in polymer membranes
成果类型：
Article
署名作者：
Wang, Anqi; Breakwell, Charlotte; Foglia, Fabrizia; Tan, Rui; Lovell, Louie; Wei, Xiaochu; Wong, Toby; Meng, Naiqi; Li, Haodong; Seel, Andrew; Sarter, Mona; Smith, Keenan; Alvarez-Fernandez, Alberto; Furedi, Mate; Guldin, Stefan; Britton, Melanie M.; McKeown, Neil B.; Jelfs, Kim E.; Song, Qilei
署名单位：
Imperial College London; Imperial College London; University of London; University College London; University of Birmingham; UK Research & Innovation (UKRI); Science & Technology Facilities Council (STFC); STFC Rutherford Appleton Laboratory; University of London; Royal Holloway University London; University of London; University College London; University of Edinburgh; King Abdullah University of Science & Technology
刊物名称：
Nature
ISSN/ISSBN：
0028-6554
DOI：
10.1038/s41586-024-08140-2
发表日期：
2024-11-14
关键词：
摘要：
Ion-conducting polymer membranes are essential in many separation processes and electrochemical devices, including electrodialysis1, redox flow batteries2, fuel cells3 and electrolysers4,5. Controlling ion transport and selectivity in these membranes largely hinges on the manipulation of pore size. Although membrane pore structures can be designed in the dry state6, they are redefined upon hydration owing to swelling in electrolyte solutions. Strategies to control pore hydration and a deeper understanding of pore structure evolution are vital for accurate pore size tuning. Here we report polymer membranes containing pendant groups of varying hydrophobicity, strategically positioned near charged groups to regulate their hydration capacity and pore swelling. Modulation of the hydrated micropore size (less than two nanometres) enables direct control over water and ion transport across broad length scales, as quantified by spectroscopic and computational methods. Ion selectivity improves in hydration-restrained pores created by more hydrophobic pendant groups. These highly interconnected ion transport channels, with tuned pore gate sizes, show higher ionic conductivity and orders-of-magnitude lower permeation rates of redox-active species compared with conventional membranes, enabling stable cycling of energy-dense aqueous organic redox flow batteries. This pore size tailoring approach provides a promising avenue to membranes with precisely controlled ionic and molecular transport functions. A method for design of polymer membranes uses strategically placed pendant groups with specific hydrophobicity to precisely tailor hydrated pore size, with applications in ion-conducting membranes for redox flow batteries.