Dupre, N., Oliveri, J., Degryse, J., Martin, J.-F. & Guyomard, D. (2008) Characterization of the surface of positive electrodes for Li-ion batteries using (7)Li MAS NMR. Ionics, 14 203–207.
Added by: Laurent Cournède (2016-03-10 21:58:41)
|Type de référence: Article
Numéro d'identification (ISBN etc.): 0947-7047
Clé BibTeX: Dupre2008a
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Mots-clés: electrochemical-behavior, Interface, layers, LiFePO4, Lithium batteries, MAS NMR, Oxides, phases, Sol-gel, spectroscopy, system, thin-films, x-ray-diffraction
Créateurs: Degryse, Dupre, Guyomard, Martin, Oliveri
Consultations : 8/439
Indice de consultation : 2%
Indice de popularité : 0.5%
The growth and evolution of the interphase, due to contact with the ambient atmosphere or electrolyte, are followed using (7)Li magic-angle spinning nuclear magnetic resonance (MAS NMR) in the case of two materials amongst the most promising candidates for positive electrodes for lithium batteries: LiFePO(4) and LiMn(0.5)Ni(0.5)O(2). The use of appropriate experimental conditions to acquire the NMR signal allows observing only the "diamagnetic" lithium species at the surface of the grains of active material. The reaction of LiMn(0.5)Ni(0.5)O(2) with the ambient atmosphere or LiPF(6) (1 M in Ethylene Carbonate/DiMethyl Carbonate (EC/DMC)) electrolyte is extremely fast and leads to an important amount of lithium-containing diamagnetic species compared to what can be observed in the case of LiFePO(4). The two studied materials display a completely different surface chemistry in terms of reactivity and/or kinetics of the surface towards electrolyte. Moreover, these results show that MAS NMR is a very promising tool to monitor phenomena taking place at the interface between electrode and electrolyte.
Added by: Laurent Cournède