title: Mechanistic Role of Li⁺ Dissociation Level in Aprotic Li-O₂ Battery.
abstract: The kinetics and thermodynamics of oxygen reduction reactions (ORR) in aprotic Li electrolyte were shown to be highly dependent on the surrounding chemical environment and electrochemical conditions. Numerous reports have demonstrated the importance of high donor number (DN) solvents for enhanced ORR, and attributed this phenomenon to the stabilizing interactions between the reduced oxygen species and the solvent molecules. We focus herein on the often overlooked effect of the Li salt used in the electrolyte solution. We show that the level of dissociation of the salt used plays a significant role in the ORR, even as important as the effect of the solvent DN. We clearly show that the salt used dictates the kinetics and thermodynamic of the ORR, and also enables control of the reduced Li2O2 morphology. By optimizing the salt composition, we have managed to demonstrate a superior ORR behavior in diglyme solutions, even when compared to the high DN DMSO solutions. Our work paves the way for optimization of various solvents with reasonable anodic and cathodic stabilities, which have so far been overlooked due to their relatively low DN.
authors: Department of Chemistry, Bar Ilan University , Ramat-Gan 52900, Israel.
authors: Daniel
authors: D
authors: Sharon
authors: Department of Chemistry, Bar Ilan University , Ramat-Gan 52900, Israel.
authors: Daniel
authors: D
authors: Hirsberg
authors: Department of Chemistry, Bar Ilan University , Ramat-Gan 52900, Israel.
authors: Michael
authors: M
authors: Salama
authors: Department of Chemistry, Bar Ilan University , Ramat-Gan 52900, Israel.
authors: Michal
authors: M
authors: Afri
authors: Department of Chemistry, Bar Ilan University , Ramat-Gan 52900, Israel.
authors: Aryeh A
authors: AA
authors: Frimer
authors: Department of Materials Science & Engineering and Institute for Systems Research, University of Maryland , College Park, Maryland 20742, United States.
authors: Malachi
authors: M
authors: Noked
authors: Department of Energy Engineering, Hanyang University , Seoul 133-791, South Korea.
authors: Wonjin
authors: W
authors: Kwak
authors: Department of Energy Engineering, Hanyang University , Seoul 133-791, South Korea.
authors: Yang-Kook
authors: YK
authors: Sun
authors: Department of Chemistry, Bar Ilan University , Ramat-Gan 52900, Israel.
authors: Doron
authors: D
authors: Aurbach
keywords: EQCM; Li−O2 batteries; glyme solvents; ionic association; lithium salts