Solid State Batteries

Ionic Liquids as Designed Components of Solid Polymer Electrolyte Architectures The intentional functional integration of ionic liquids ILs into polymer networks and polymers with designed confinement enables lithium and beyond-lithium solid polymer electrolytes to reach reasonable room-temperature ionic conductivity 104 S/cm) and to balance the trade-off with mechanical strength and interfacial instability. Ionic liquid incorporation not only acts as a plasticizer, but has been shown to improve contact at metal interfaces, suppress dendrites and brittle fracture, improve thermal stability, and enable self-adaptive, viscous behavior. The structural integration of ILs to polymer networks produces a “liquid-likeˮ matrix that enables high ionic conductivity within a mechanically robust electrolyte film.

Room-Temperature ionic conductivity of sodium quasi-solid polymer electrolytes upon varying amount of plasticizer.

In sodium systems, IL incorporation can be used to alter the anion-polymer interactions to increase cation diffusivity. Novel blending strategies have enabled long cell cycling and excellent fuel-cell performance. In potassium systems, ILs enabled ionic conductivity above 103 S/cm and positivity influenced stable SEI formation.

Solid polymer electrolytes that structurally integrate ionic liquids have emerged as a key design trend that has enabled room-temperature conductivity, improved ion coordination and mobility, and stable metal anodes in beyond-lithium solid-state batteries.

Flammability test photos of fabricated composite IL-polymer lithium electrolyte films

Source: 1 Kala, V. S., Soni, C. B., Sungjammenla, et. al. J. Mater. Chem. A. 2025. 2 Chen, J., Ebrahimi-Koodehi, S., Iliev, B., et. al. J. Mater. Chem. A. 2025. 3 Makhlooghiazad, F., Mejia, L. M. G., Rollo-Walker, G., et. al., J. Am. Chem. Soc. 2024 4 Chae, W., Earmme, T. ACS Omega, 2025

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