Dupre, N., Cuisinier, M., Legall, E., War, D. & Guyomard, D. (2015) Contribution of the oxygen extracted from overlithiated layered oxides at high potential to the formation of the interphase. J. Power Sources, 299 231–240.
Added by: Laurent Cournède (2016-03-10 18:36:40)
|Type de référence: Article
Numéro d'identification (ISBN etc.): 0378-7753
Clé BibTeX: Dupre2015
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Mots-clés: Cathode material, electrochemical-behavior, high-voltage, Li-ion battery, LiF, lipf6-based electrolytes, Lithium-ion batteries, MAS NMR, NMR, Parasitic reactions, positive electrode interface, simple combustion method, Surface, thermal-stability, x-ray-diffraction
Créateurs: Cuisinier, Dupre, Guyomard, Legall, War
Collection: J. Power Sources
Consultations : 5/409
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Li-rich (1-x)LiMO2 center dot xLi(2)MnO(3) layered oxides materials have been proposed recently as an attractive alternative to LiCoO2 Their electrochemical performance is greatly improved by charging above the 4.5 -4.6 V voltage plateau during the first oxidation. The associated reaction mechanism has been assigned to a transformation from layered to spinel, accompanied a partial oxygen removal process from the surface. Nevertheless, many questions are still unanswered concerning the influence of oxygen extraction and reaction on the chemical composition and evolution of the electrode/electrolyte interphase. Quantitative Li-7, F-19 and P-31 MAS NMR shows that the partial oxygen extraction at the surface of the electrode material above 4.5 V has a strong influence on the composition/nature of the interphase and exacerbates reactions at the electrode/electrolyte interface. Oxygen reacts as soon as it is extracted from the structure of the positive electrode material to form fluorophosphates in much higher amount in the case of the overlithiated material compared to the stoichiometric material exposed to comparable potentials. The presented study indicates that the release of oxygen from the Li-rich layered oxides greatly influences the electrode/electrolyte interphasial chemistry. (C) 2015 Elsevier B.V. All rights reserved.
Added by: Laurent Cournède