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DOE OSTI · 2589419

Dynamical Ion Correlations in Polymer and Membrane Electrolytes: Recent Advances and Open Questions

Ganesan, Venkat [University of Texas at Austin, TX (United States)] (ORCID:0000000338995843)·Zhang, Zidan [University of Texas at Austin, TX (United States)] (ORCID:0000000269098742)·Marioni, Nico [University of Texas at Austin, TX (United States)] (ORCID:0009000123073064)
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Abstract

Ion transport in polymer and membrane electrolytes is often described using uncorrelated models like the Nernst–Einstein (NE) approximation, which link conductivity, transference number, and salt diffusivity to individual ion mobilities. However, growing evidence shows that dynamical ion correlations─arising from ion pairing, polymer-mediated coupling, confinement, and electrostatic interactions─can substantially alter macroscopic transport properties. The Onsager transport formalism offers a rigorous framework to quantify these effects via cross-correlated ionic displacements. This Perspective highlights how such correlations manifest across dry and hydrated systems, including salt-doped polymers, block copolymers, hydrogels, and ion-exchange membranes. Here, we examine key physical origins, the influence of salt chemistry and polymer structure, and open questions in measuring and controlling correlated motion. Embracing correlation-aware design enables new pathways to optimize conductivity, transference number, and selectivity─shifting the focus from individual ion mobility to engineered collective dynamics for next-generation electrolytes in energy storage and separations.

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Charge transportIonsMembranesPolymersSalts

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Ganesan, Venkat [University of Texas at Austin, TX (United States)] (ORCID:0000000338995843), Zhang, Zidan [University of Texas at Austin, TX (United States)] (ORCID:0000000269098742), Marioni, Nico [University of Texas at Austin, TX (United States)] (ORCID:0009000123073064). 2025-08-01. Dynamical Ion Correlations in Polymer and Membrane Electrolytes: Recent Advances and Open Questions. https://doi.org/10.1021/acs.jpclett.5c02006

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