Understanding the behavior of Li-oxygen cells containing LiI

Won Jin Kwak, Daniel Hirshberg, Daniel Sharon, Hyeon Ji Shin, Michal Afri, Jin Bum Park, Arnd Garsuch, Frederick Francois Chesneau, Aryeh A. Frimer, Doron Aurbach, Yang Kook Sun

Research output: Contribution to journalArticlepeer-review

181 Scopus citations

Abstract

Mankind has been in an unending search for efficient sources of energy. The coupling of lithium and oxygen in aprotic solvents would seem to be a most promising direction for electrochemistry. Indeed, if successful, this system could compete with technologies such as the internal combustion engine and provide an energy density that would accommodate the demands of electric vehicles. All this promise has not yet reached fruition because of a plethora of practical barriers and challenges. These include solvent and electrode stability, pronounced overvoltage for oxygen evolution reactions, limited cycle life and rate capability. One of the approaches suggested to facilitate the oxygen evolution reactions and improve rate capability is the use of redox mediators such as iodine for the fast oxidation of lithium peroxide. In this paper we have examined LiI as an electrolyte and additive in Li oxygen cells with ethereal electrolyte solutions. At high concentrations of LiI, the presence of the salt promotes a side reaction that forms LiOH as a major product. In turn, the presence of oxygen facilitates the reduction of I3- to 3I- in these systems. At very low concentrations of LiI, oxygen is reduced to Li2O2. The iodine formed in the anodic reaction serves as a redox mediator for Li2O2 oxidation.

Original languageEnglish
Pages (from-to)8855-8864
Number of pages10
JournalJournal of Materials Chemistry A
Volume3
Issue number16
DOIs
StatePublished - 28 Apr 2015

Bibliographical note

Publisher Copyright:
© 2015 The Royal Society of Chemistry.

Funding

FundersFunder number
National Research Foundation of Korea

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