Experimental and Theoretical Determination of Limiting Current of SEO/LiTFSI Block Copolymer Electrolytes from the Dilute Limit to the Solubility Limit

作者：Lily A. Gido, Eric Schaible, Chenhui Zhu, Nitash P. Balsara · 发表于：Macromolecules · 年份：2025 · DOI：10.1021/acs.macromol.5c00929 · 被引用次数：3 · 研究领域：Advanced Battery Materials and Technologies、Advancements in Battery Materials、Advanced Battery Technologies Research

Polystyrene- block -poly(ethylene oxide) (SEO) block copolymer electrolytes microphase separate into conductive poly(ethylene oxide) (PEO) domains and polystyrene (PS) domains which provide mechanical robustness. This leads to suppression of dendrite growth at the surface of lithium metal electrodes. We exploit this to measure the limiting current in SEO/lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) electrolytes in the r = 0.01 to r = 0.50 concentration range, where r is defined as the molar ratio of lithium ions to ethylene oxide monomer units. We report the full electrochemical characterization of these electrolytes enabling theoretical prediction of the dependence of limiting current on salt concentration using concentrated solution theory. Using small-angle X-ray scattering, we show that our electrolytes have a lamellar morphology across the entire concentration window. The passage of large currents results in swelling of the lamellae near the positive electrode and deswelling near the negative electrode which concentrated solution theory does not account for.