Kwak, Won-Jin Kim, Hun Jung, Hun-Gi Aurbach, Doron Sun, Yang-Kook 2024-01-19T22:31:32Z 2024-01-19T22:31:32Z 2021-09-03 2018-07 0013-4651 https://pubs.kist.re.kr/handle/201004/121224 For resolving the low-energy efficiency issue of Li-O-2 batteries, many kinds of redox mediators (RMs) have been adapted. However, studies looking into the problems of RMs in these systems are insufficient. We compare herein effects and problems of RMs in Li-O-2 batteries by applying unique methodology, based on two types of cells, comparison between argon and oxygen atmospheres and combining electrochemistry in conjunction with spectroscopy. Using systematic electrochemical measurements, representative RMs in Li-O-2 battery prototypes were thoroughly explored with respect to oxygen presence, voltage ranges and scan rates. By this comparative, multi-parameters study we reached valuable insights. We identified possible routes for RMs degradation in Li-O-2 batteries related to the cathode side, using bi-compartments cells with solid electrolyte that blocks the crossover between the cathode and the Li metal sides. Based on comparative electrochemical and spectroscopic analyses, we confirmed that degradation of the RMs activity was caused by intrinsic decomposition of the RMs in the electrolyte solution at the cathode part, even before further reactions with reduced oxygen species. This work provides a realistic view of the role of important RMs in Li-oxygen cells and suggests guidelines for effective screening and selecting suitable RMs, mandatory components in Li-O-2 batteries. (C) The Author(s) 2018. Published by ECS. English ELECTROCHEMICAL SOC INC LITHIUM-OXYGEN BATTERIES LI-AIR BATTERIES SUPPRESSING CHARGING INSTABILITIES EVOLUTION REACTIONS LI2O2 OXIDATION CARBON ELECTROLYTE STABILITY REDUCTION CATALYST Review-A Comparative Evaluation of Redox Mediators for Li-O-2 Batteries: A Critical Review Article 10.1149/2.0901810jes 1 JOURNAL OF THE ELECTROCHEMICAL SOCIETY, v.165, no.10, pp.A2274 - A2293 JOURNAL OF THE ELECTROCHEMICAL SOCIETY 165 10 A2274 A2293 scie scopus 000441061800038 2-s2.0-85053760691 Electrochemistry Materials Science, Coatings & Films Electrochemistry Materials Science Review LITHIUM-OXYGEN BATTERIES LI-AIR BATTERIES SUPPRESSING CHARGING INSTABILITIES EVOLUTION REACTIONS LI2O2 OXIDATION CARBON ELECTROLYTE STABILITY REDUCTION CATALYST