XPS ANALYSIS OF THE SURFACE OF A CARBON ELECTRODE INTERCALATED BY LITHIUM IONS

Citation
K. Kanamura et al., XPS ANALYSIS OF THE SURFACE OF A CARBON ELECTRODE INTERCALATED BY LITHIUM IONS, Chemistry of materials, 9(8), 1997, pp. 1797-1804
Citations number
26
Categorie Soggetti
Chemistry Physical","Material Science
Journal title
ISSN journal
08974756
Volume
9
Issue
8
Year of publication
1997
Pages
1797 - 1804
Database
ISI
SICI code
0897-4756(1997)9:8<1797:XAOTSO>2.0.ZU;2-L
Abstract
Surface states of carbon electrodes reduced in nonaqueous electrolytes containing 1.0 mol dm(-3) LiClO4 were analyzed by an X-ray photoelect ron spectroscopy (XPS) in order to decide chemical compositions of sur face films formed on two different carbon materials. One is a low crys talline carbon, and the other is a highly crystalline carbon. The XPS spectra measured in this study suggest that the chemical compositions of the surface film formed on the highly crystalline carbon depends on the type of solvent. The carbon surface was almost bare when using pr opylene carbonate. On the other hand, a well-defined surface film main ly consisting of LiOH was formed in a mixed solvent of ethylene carbon ate and diethyl carbonate. When the low crystalline carbon was used, t he surface films formed in both electrolytes were a well-developed lay er mainly consisting of LiOH. The electrochemical characteristics of t hese carbon materials in the two electrolytes showed that irreversible reactions were suppressed by the formation of a well-developed LiOH l ayer. These results suggested that such a well-developed LiOH layer fo rmed on carbon materials has a function to suppress the irreversible r eactions occurring on carbon materials during the first cathodic reduc tion process.