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Electroreduction of graphite in LiClO4-ethylene carbonate electrolyte. Characterization of the passivating layer by transmission electron microscopy and Fourier-transform infrared spectroscopy
- Source :
- Journal of Power Sources. 63:33-39
- Publication Year :
- 1996
- Publisher :
- Elsevier BV, 1996.
-
Abstract
- Electrochemical intercalation of unsolvated lithium into pitch carbon fibres P100 and natural graphite UF4 has been carried out in LiClO4-ethylene carbonate electrolyte. The reversible electrochemical capacity for a current equal to 7 μA/mg is 260 mAh/g for P100 carbon fibres and about 350 mAh/g for UF4 graphite, respectively. During the first discharge (reduction) an electrochemical capacity greater than the theoretical value (372 mAh/g) corresponding to LiC6 is obtained. This excess of capacity can be related to the formation of a passivating layer on the carbon surface. Analysis of this layer by means of transmission electron microscopy (electron diffraction, electron energy loss spectroscopy, and imaging) and Fourier-transform infrared spectroscopy has shown that this layer is composed of lithium carbonate Li2CO3 and alkylcarbonates of lithium ROCO2Li. Formation of Li2CO3 occurs at potentials in the 1−0.8 V range versus Li + Li , and formation of lithium alkylcarbonates then follows at potentials below 0.8 V. We then attributed the voltage plateau at 0.9 V versus Li + Li observed in the electrochemical waves to the reduction of ethylene carbonate into Li2CO3. Transmission electron spectroscopy revealed the presence of lithium chloride in the electrolyte which appears as small rods.
- Subjects :
- Renewable Energy, Sustainability and the Environment
Electron energy loss spectroscopy
Lithium carbonate
Analytical chemistry
Energy Engineering and Power Technology
chemistry.chemical_element
Electrolyte
Lithium perchlorate
chemistry.chemical_compound
chemistry
Electron diffraction
Lithium chloride
Lithium
Electrical and Electronic Engineering
Physical and Theoretical Chemistry
Ethylene carbonate
Subjects
Details
- ISSN :
- 03787753
- Volume :
- 63
- Database :
- OpenAIRE
- Journal :
- Journal of Power Sources
- Accession number :
- edsair.doi...........a5abc2d0bbabec2da192a39eaae60aec