Contribution of the oxygen extracted from overlithiated layered oxides at high potential to the formation of the interphase

Nicolas Dupré, Marine Cuisinier, Erwan Legall, Djibril War, Dominique Guyomard

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

Li-rich (1-x)LiMO2.xLi2MnO3 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 7Li, 19F and 31P 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.

Original languageEnglish
Pages (from-to)231-240
Number of pages10
JournalJournal of Power Sources
Volume299
DOIs
Publication statusPublished - 20 Dec 2015
Externally publishedYes

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Keywords

  • Li-ion battery
  • LiF
  • NMR
  • Parasitic reactions
  • Surface

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Energy Engineering and Power Technology
  • Renewable Energy, Sustainability and the Environment
  • Physical and Theoretical Chemistry

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