Comparing measurement of limiting current in block copolymer electrolytes as a function of salt concentration with theoretical predictions

Optimizing electrolyte performance is crucial for the widespread adoption of electrochemical energy stor -age. We demonstrate that limiting current provides a robust criterion for determining the optimum electrolyte. Experiments were conducted on rigid block copolymer electrolytes comprising mixtures of polystyrene-block-poly(ethylene oxide) copolymer (SEO) and lithium bis(trifluoromethanesulfonyl) imide salt (LiTFSI) over a salt concentration range from r(av) = 0.04 to r(av) = 0.20 (r(av) is the molar ratio of lithium ions to ethylene oxide). We show that the maximum limiting current density is 4.3 mA cm (-2) at r(av) = 0.12. The dependence of limiting current on salt concentration is in good agreement with predictions from Newman's concentrated solution theory with no adjustable parameters. (C) 2022 Elsevier Ltd. All rights reserved.

Automated summary

Optimizing electrolyte performance is crucial for electrochemical energy storage, and we demonstrate that limiting current can serve as a robust criterion for determining the optimum electrolyte. Through experiments and theoretical analysis, we identify the condition of maximum limiting current density in a rigid block copolymer electrolyte with a salt concentration of r(av) = 0.12.