article published yes Pronoy Dutta author Jean Marc Von Mentlen author Soumyadip Mondal author d25d21ef-dc8d-11ea-abe3-ec4576307f48 Nikolaos Kostoglou author Bodo D. Wilts author Stefan Alexander Freunberger author A8CA28E6-CE23-11E9-AD2D-EC27E66974250000-0003-2902-5319 Gregor A. Zickler author Christian Prehal author StFr department “Quasi-solid-state” conversion mechanisms using sparingly solvating electrolytes (SPSEs) bridge the gap between traditional solid–liquid–solid and solid-state sulfur conversion in lithium–sulfur (Li–S) batteries. Although these terms are commonly used, their precise distinctions and impacts on key performance metrics, such as rate capability, energy density, and capacity fading, remain poorly understood. In this work, we employ operando small- and wide-angle X-ray scattering alongside cryogenic transmission electron microscopy (cryo-TEM) to compare Li–S batteries in sparingly solvating and solvating ether-based electrolytes. We find that, unlike solvating electrolytes, SPSEs lead to an extended presence of lithium sulfide during cycling, coexisting with sulfur at a 50% state of charge and beyond. In the charged state, solid sulfur is present in its amorphous form inside the carbon black nanopores. These findings indicate that the limited solubility confines polysulfides in regions near the carbon surface, where these polysulfides enable conversion between the coexisting solid discharge and charge product. https://research-explorer.ista.ac.at/download/20593/20597/2025_ACSEnergyLetters_Dutta.pdf application/pdfno https://creativecommons.org/licenses/by/4.0/ American Chemical Society2025 eng 2380-8195 00160039600000110.1021/acsenergylett.5c02093 105722-5732 https://doi.org/10.5281/zenodo.17144229 Dutta, Pronoy, Jean Marc Von Mentlen, Soumyadip Mondal, Nikolaos Kostoglou, Bodo D. Wilts, Stefan Alexander Freunberger, Gregor A. Zickler, and Christian Prehal. “Bridging Solution and Solid-State Mechanism: Confined Quasi-Solid-State Conversion in Li–S Batteries.” <i>ACS Energy Letters</i>. American Chemical Society, 2025. <a href="https://doi.org/10.1021/acsenergylett.5c02093">https://doi.org/10.1021/acsenergylett.5c02093</a>. Dutta P, Von Mentlen JM, Mondal S, et al. Bridging solution and solid-state mechanism: Confined quasi-solid-state conversion in Li–S batteries. <i>ACS Energy Letters</i>. 2025;10:5722-5732. doi:<a href="https://doi.org/10.1021/acsenergylett.5c02093">10.1021/acsenergylett.5c02093</a> Dutta P, Von Mentlen JM, Mondal S, Kostoglou N, Wilts BD, Freunberger SA, Zickler GA, Prehal C. 2025. Bridging solution and solid-state mechanism: Confined quasi-solid-state conversion in Li–S batteries. ACS Energy Letters. 10, 5722–5732. P. Dutta, J.M. Von Mentlen, S. Mondal, N. Kostoglou, B.D. Wilts, S.A. Freunberger, G.A. Zickler, C. Prehal, ACS Energy Letters 10 (2025) 5722–5732. Dutta, P., Von Mentlen, J. M., Mondal, S., Kostoglou, N., Wilts, B. D., Freunberger, S. A., … Prehal, C. (2025). Bridging solution and solid-state mechanism: Confined quasi-solid-state conversion in Li–S batteries. <i>ACS Energy Letters</i>. American Chemical Society. <a href="https://doi.org/10.1021/acsenergylett.5c02093">https://doi.org/10.1021/acsenergylett.5c02093</a> Dutta, Pronoy, et al. “Bridging Solution and Solid-State Mechanism: Confined Quasi-Solid-State Conversion in Li–S Batteries.” <i>ACS Energy Letters</i>, vol. 10, American Chemical Society, 2025, pp. 5722–32, doi:<a href="https://doi.org/10.1021/acsenergylett.5c02093">10.1021/acsenergylett.5c02093</a>. P. Dutta <i>et al.</i>, “Bridging solution and solid-state mechanism: Confined quasi-solid-state conversion in Li–S batteries,” <i>ACS Energy Letters</i>, vol. 10. American Chemical Society, pp. 5722–5732, 2025. 205932025-11-02T23:01:35Z2025-12-01T15:11:44Z