Influence of Water Sorption on Ionic Conductivity in Polyether Electrolytes at Low Hydration

IF 5.1 Q1 POLYMER SCIENCE

ACS Macro Letters Pub Date : 2024-12-23 DOI:10.1021/acsmacrolett.4c00707

Rahul Sujanani, Phong H. Nguyen, Leo W. Gordon, James T. Bamford, Alexandra Zele, Benjamin J. Pedretti, Nathaniel A. Lynd, Raphaële J. Clément, Rachel A. Segalman

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引用次数: 0

Abstract

Ion-containing polymers are subject to a wide range of hydration conditions across electrochemical and water treatment applications. Significant work on dry polymer electrolytes for batteries and highly swollen membranes for water purification has informed our understanding of ion transport under extreme conditions. However, knowledge of intermediate conditions (i.e., low hydration) is essential to emerging applications (e.g., electrolyzers, fuel cells, and lithium extraction). Ion transport under low levels of hydration is distinct from the extreme conditions typically investigated, and the relevant physics cannot be extrapolated from existing knowledge, stifling materials design. In this study, we conducted ion transport measurements in LiTFSI-doped polyethers that were systematically hydrated from dry conditions. A semiautomated apparatus that performs parallel measurements of water uptake and ionic conductivity in thin-film polymers under controlled humidity was developed. For the materials and swelling range considered in this study (i.e., <0.07 g water/g dry polymer electrolyte), ionic conductivity depends nonlinearly on water uptake, with the initial sorbed water weakly affecting conductivity. With additional increases in swelling, more significant increases in conductivity were observed. Remarkably, changes in conductivity induced by water sorption were correlated with the number of water molecules per lithium ion, with the normalized molar conductivity of different samples effectively collapsing onto one another until this unit of hydration exceeded the solvation number of lithium ions under aqueous conditions. These results provide important knowledge regarding the effects of trace water contamination on conductivity measurements in polymer electrolytes and demonstrate that the lithium-ion solvation number marks a key transition point regarding the influence of water on ion transport in ion-containing polymers.

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来源期刊

ACS Macro Letters 化学-

CiteScore

10.40

自引率

3.40%

发文量

209

审稿时长

1 months

期刊介绍： ACS Macro Letters publishes research in all areas of contemporary soft matter science in which macromolecules play a key role, including nanotechnology, self-assembly, supramolecular chemistry, biomaterials, energy generation and storage, and renewable/sustainable materials. Submissions to ACS Macro Letters should justify clearly the rapid disclosure of the key elements of the study. The scope of the journal includes high-impact research of broad interest in all areas of polymer science and engineering, including cross-disciplinary research that interfaces with polymer science. With the launch of ACS Macro Letters, all Communications that were formerly published in Macromolecules and Biomacromolecules will be published as Letters in ACS Macro Letters.