Reactions and SEI Formation during Charging of Li-O2 Cells. (1st January 2015)

• Record Type: Journal Article
• Authors: Højberg, Jonathan; Knudsen, Kristian Bastholm; Hjelm, Johan; Vegge, Tejs
• Is Part Of: ECS Electrochemistry Letters. Volume 4:Number 7(2015)
• Page Start: A63
• Page End: A66
• Publication Date: 2015-01-01
• Subjects: degradation -- DEMS -- EIS -- Li-O2 -- overpotential -- SEI
• DOI: 10.1149/2.0051507eel
• Languages: English
• ISSNs: 2162-8726

Abstract

Abstract : In this letter we combine detailed electrochemical impedance measurements with quantitative measurements of O2 evolution and Li2 O2 oxidation to describe the charge mechanisms during charge of Li-O2 batteries with porous carbon electrodes. We identify Li2 O2 oxidation at 3.05 V and an apparent chemical formation of a solid electrolyte interface (SEI) layer as the first monolayer of Li2 O2 is oxidized, leading to a voltage increase. The first electrochemical degradation reaction is identified between 3.3 V and 3.5 V, and the chemical degradation is limited above 3.5 V, suggesting that a chemically stable SEI layer has been formed.