Hrtem imaging and EELS spectroscopy of lithiation process in FeFx:C nanocomposites

F. Cosandey, J. F. Al-Sharab, F. Badway, G. G. Amatucci

Research output: Contribution to journalConference articlepeer-review

2 Scopus citations

Abstract

A new type of positive electrodes for Li-Ion batteries has been developed based on FeF 3:C carbon metal fluoride nanocomposites. The electrochemical data reveal a reversible metal fluoride conversion process with a high specific capacity of about 600 mAh/g realized at 70°C. The nanocomposite electrodes were analyzed after synthesis as well as upon voltage cycling from 4.5 to 1.5V by combined selected area electron diffraction (SAED), high-resolution transmission electron microscopy (HRTEM) and electron energy-loss spectroscopy (EELS) techniques. HRTEM combined with SAED were used for phase identification while EELS was used to determine the valence state of Fe from L 3 energy shift as well as white line L 3/L 2 intensity ratio. After synthesis, the microstructure is composed of FeF 3 nano-crystal of the order of 15 nm encompassed in a matrix of carbon. Upon discharged to 1.5V, a complete reduction of iron to Fe o is observed with the formation of a finer Fe:LiF:C nanocomposites (∼8 nm). Upon recharging to 4.5V, EELS and HRTEM data reveal a reoxidation process to a Fe 2+ state with the formation of a carbon metal fluoride nanocomposite related to the Fep 2 structure.

Original languageEnglish (US)
Pages (from-to)111-119
Number of pages9
JournalCeramic Transactions
Volume161
StatePublished - 2005
Event106th Annual Meeting of the American Ceramic Society - Indianapolis, IN, United States
Duration: Apr 18 2004Apr 21 2004

All Science Journal Classification (ASJC) codes

  • Ceramics and Composites
  • Materials Chemistry

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