title: Reactive oxygen species formed in organic lithium-oxygen batteries.
abstract: Li-oxygen batteries with organic electrolytes are of general interest because of their theoretically high gravimetric energy density. Among the great challenges for this storage technology is the generation of reactive oxygen species such as superoxides and peroxides that may react with the organic solvent molecules and other cell components. The generation of such species has been assumed to occur during the charging reaction. Here we show that superoxide is formed also during the discharge reaction in lithium ion-containing dimethyl sulfoxide electrolytes and is released into the solution. This is shown independently by fluorescence microscopy after reaction with the selective reagent 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole and by local detection using a microelectrode of a scanning electrochemcial microscope positioned in a defined distance of 10 to 90 μm above the gas diffusion electrode.
authors.affiliation: Carl von Ossietzky University, Faculty of Mathematics and Natural Sciences, Center of Interface Science, Institute of Chemistry, D-26111 Oldenburg, Germany. gunther.wittstock@uni-oldenburg.de and Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM, Wiener Straße 12, D-28359 Bremen, Germany.
authors.forename: Patrick
authors.initials: P
authors.lastname: Schwager
authors.affiliation: Carl von Ossietzky University, Faculty of Mathematics and Natural Sciences, Center of Interface Science, Institute of Chemistry, D-26111 Oldenburg, Germany. gunther.wittstock@uni-oldenburg.de.
authors.forename: Saustin
authors.initials: S
authors.lastname: Dongmo
authors.affiliation: Fraunhofer Institute for Manufacturing Technology and Advanced Materials IFAM, Wiener Straße 12, D-28359 Bremen, Germany.
authors.forename: Daniela
authors.initials: D
authors.lastname: Fenske
authors.affiliation: Carl von Ossietzky University, Faculty of Mathematics and Natural Sciences, Center of Interface Science, Institute of Chemistry, D-26111 Oldenburg, Germany. gunther.wittstock@uni-oldenburg.de.
authors.forename: Gunther
authors.initials: G
authors.lastname: Wittstock