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DOE OSTI · 3728565

Unique Conductivity Behavior in Water-In-Salt Electrolytes Driven by Ion Clusters

Nguyen, Huong T. D.·Lee, Shao-Chun·Lyu, Xingyi·Fang, Lingzhe·Trojanowski, Lucas·Gonzalez, Rena·Harr, MJ·Rai, Lalita·Z, Y·Li, Tao
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Abstract

Understanding and predicting ion transport in aqueous electrolytes are crucial for advanced energy storage and biophysics, and many emergent technologies yet remain elusive. Herein, we introduce a unified framework to quantitatively describe and predict electrolyte conductivity that shifts from conventional molar concentration-based metrics to a volume fraction-based approach. Through analyzing a variety of electrolyte solutions via this perspective, we observe a universal conductivity peak at a 37% volume fraction. Small-angle X-ray scattering (SAXS) and molecular dynamics (MD) simulations reveal that nanometer-scale ion clusters drive this general behavior. Moreover, key geometric features of the ion transport pathwayssuch as pore size, tortuosity, and connectivityfollow a consistent dependence with respect to the volume fraction, reinforcing the argument for the universal conductivity trend. This paradigm shift opens new avenues for designing high-performance electrolytes and provides transformative insights for advancing studies in many fields, wherein molecular aggregates dictate transport properties.

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Nguyen, Huong T. D., Lee, Shao-Chun, Lyu, Xingyi, Fang, Lingzhe, Trojanowski, Lucas, Gonzalez, Rena, Harr, MJ, Rai, Lalita, Z, Y, Li, Tao. 2025-07-30. Unique Conductivity Behavior in Water-In-Salt Electrolytes Driven by Ion Clusters. https://doi.org/10.1021/jacs.5c07370

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