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Oxygen Reduction by Lithiated Graphene and Graphene-Based Materials

Authors/others:Kataev, Elmar Yu (Lomonosov Moscow State University (MSU)) Itkis, Daniil M. (Lomonosov Moscow State University (MSU)) Fedorov, Alexander V. (Universität zu Köln) Senkovsky, Boris V. (Technische Universität Dresden) Usachov, Dmitry Yu (Saint Petersburg State University) Verbitskiy, Nikolay I. (Lomonosov Moscow State University (MSU)) Grüneis, Alexander (Universität zu Köln) Barinov, Alexei (Elettra Sincrotrone Trieste) Tsukanova, Daria Yu (Lomonosov Moscow State University (MSU)) Volykhov, Andrey A. (Lomonosov Moscow State University (MSU)) Mironovich, Kirill V. (Lomonosov Moscow State University (MSU)) Krivchenko, Victor A. (Lomonosov Moscow State University (MSU)) Rybin, Maksim G. (Russian Academy of Sciences) Obraztsova, Elena D. (Russian Academy of Sciences) Laubschat, Clemens (Technische Universität Dresden) Vyalikh, Denis V. (Technische Universität Dresden) Yashina, Lada V. (Lomonosov Moscow State University (MSU))
Abstract:Oxygen reduction reaction (ORR) plays a key role in lithium-air batteries (LABs) that attract great attention thanks to their high theoretical specific energy several times exceeding that of lithium-ion batteries. Because of their high surface area, high electric conductivity, and low specific weight, various carbons are often materials of choice for applications as the LAB cathode. Unfortunately, the possibility of practical application of such batteries is still under question as the sustainable operation of LABs with carbon cathodes is not demonstrated yet and the cyclability is quite poor, which is usually associated with oxygen reduced species side reactions. However, the mechanisms of carbon reactivity toward these species are still unclear. Here, we report a direct in situ X-ray photoelectron spectroscopy study of oxygen reduction by lithiated graphene and graphene-based materials. Although lithium peroxide (Li2O2) and lithium oxide (Li2O) reactions with carbon are thermodynamically favorable, neither of them was found to react even at elevated temperatures. As lithium superoxide is not stable at room temperature, potassium superoxide (KO2) prepared in situ was used instead to test the reactivity of graphene with superoxide species. In contrast to Li2O2 and Li2O, KO2 was demonstrated to be strongly reactive.
Number of pages:7
Date of publication:1.2015
Journal title:ACS Nano
Digital Object Identifier (DOI):http://dx.doi.org/10.1021/nn5052103
Publication Type:Article
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