In situ studies of SEI formation

Abstract Electrolyte decomposition and the formation of a solid electrolyte interphase (SEI) layer occur during the initial charge/discharge cycles of carbon in electrolytes used in Li-ion batteries. This paper describes our approach to characterize the formation of SEI layers on various carbonaceous materials by in situ ellipsometry. Five types of carbon samples (carbon films on glass, pyrolyzed photoresist on silicon, highly oriented pyrolytic graphite and natural graphite) with specular surfaces were characterized by Raman spectroscopy and in situ ellipsometry/electrochemical studies in ethylene carbonate–dimethyl carbonate containing a lithium salt. Raman spectroscopy showed that the carbons films deposited on glass contain broad overlapping peaks from 900 to 1700 cm −1 , which is indicative of the highly disordered nature of the carbon films. Changes in the ellipsometric parameters, Δ and ψ , were correlated with the formation of the SEI layer during the initial charge (intercalation) process.

[1]  J. Farmer,et al.  Fast, self‐compensating spectral‐scanning ellipsometer , 1984 .

[2]  Sven Ulrich,et al.  Raman spectroscopy on amorphous carbon films , 1996 .

[3]  F. Tuinstra,et al.  Raman Spectrum of Graphite , 1970 .

[4]  K. Zaghib,et al.  Effect of Graphite Particle Size on Irreversible Capacity Loss , 2000 .

[5]  A. Ishitani,et al.  Raman spectra of graphite edge planes , 1988 .

[6]  Rolf H. Muller,et al.  Definitions and conventions in ellipsometry , 1969 .

[7]  Rachid Yazami,et al.  Surface chemistry and lithium storage capability of the graphite-lithium electrode , 1999 .

[8]  C. Wan,et al.  Composition analysis of the passive film on the carbon electrode of a lithium-ion battery with an EC-based electrolyte , 1998 .

[9]  M. Nakamizo,et al.  Raman spectra of the oxidized and polished surfaces of carbon , 1984 .

[10]  Doron Aurbach,et al.  On the correlation between surface chemistry and performance of graphite negative electrodes for Li ion batteries , 1999 .

[11]  D. Aurbach,et al.  The Study of Electrolyte Solutions Based on Ethylene and Diethyl Carbonates for Rechargeable Li Batteries II . Graphite Electrodes , 1995 .

[12]  J. M. Stone,et al.  Radiation and Optics , 1963 .

[13]  Xiangyun Song,et al.  Electrochemical Studies of Carbon Films from Pyrolyzed Photoresist , 1998 .

[14]  E. Peled,et al.  A Study of Highly Oriented Pyrolytic Graphite as a Model for the Graphite Anode in Li‐Ion Batteries , 1999 .

[15]  Doron Aurbach,et al.  A Comparative Study of Synthetic Graphite and Li Electrodes in Electrolyte Solutions Based on Ethylene Carbonate‐Dimethyl Carbonate Mixtures , 1996 .

[16]  R. McCreery,et al.  Activation of highly ordered pyrolytic graphite for heterogeneous electron transfer: relationship between electrochemical performance and carbon microstructure , 1989 .

[17]  D. Aurbach,et al.  The Correlation Between the Surface Chemistry and the Performance of Li‐Carbon Intercalation Anodes for Rechargeable ‘Rocking‐Chair’ Type Batteries , 1994 .

[18]  D. Aurbach,et al.  Electrochemical and spectroscopic studies of carbon electrodes in lithium battery electrolyte systems , 1993 .

[19]  Ki-Young Lee,et al.  Effect of Surface Structure on the Irreversible Capacity of Various Graphitic Carbon Electrodes , 1999 .

[20]  R. McCreery,et al.  Spatially Resolved Raman Spectroscopy of Carbon Electrode Surfaces: Observations of Structural and Chemical Heterogeneity , 1997 .

[21]  G. Turban,et al.  Ellipsometry and Raman study on hydrogenated amorphous carbon (a-C:H) films deposited in a dual ECR-r.f. plasma , 1999 .

[22]  D. Aurbach,et al.  Recent studies on the correlation between surface chemistry, morphology, three-dimensional structures and performance of Li and Li-C intercalation anodes in several important electrolyte systems , 1997 .