Effect of Vinylene Carbonate Additive in Li-Ion Batteries: Comparison of LiCoO2∕C, LiFePO4∕C, and LiCoO2∕Li4Ti5O12 Systems

• Published in: Journal of the Electrochemical Society Vol. 156; no. 6
• Main Authors: El Ouatani, L., Dedryvère, Rémi, Siret, C., Biensan, P., Gonbeau, D.
• Format: Journal Article
• Language: English
• Published: Electrochemical Society 2009
• Subjects: Chemical Sciences; Material chemistry; or physical chemistry; Theoretical and; LiFePO 4; polymerization; vinylene carbonate; SEI; XPS; interface; Li-ion batteries; electrolyte additive; Li4Ti5O12
• ISSN: 0013-4651; 1945-7111
• DOI: 10.1149/1.3111891

Vinylene Carbonate (VC) is a commonly used electrolyte additive in Li-ion batteries, because of its beneficial role on the formation of the solid electrolyte interphase (SEI). It was shown to contribute to surface film formation on both electrodes of LiCoO 2 /C cells via its radical polymerization mechanism. In this paper, we carried out a comparative study of the role of VC on electrode/electrolyte interfaces in LiCoO 2 /C, LiFePO 4 /C and LiCoO 2 /Li 4 Ti 5 O 12 systems, in which the potential and the chemical nature of each electrode are changed. Coincells were charged at different potentials using a LiPF 6 /EC:DEC:DMC liquid electrolyte with or without VC, and the electrodes were analyzed by X-ray Photoelectron Spectroscopy (XPS). We showed there is no interaction between the negative and the positive electrode in the VC polymerization mechanisms-for example by exchange of chemical species from one electrode to the other one-during the first charge. Separate mechanisms occur, although the same VC polymer is deposited at the surface of both electrodes.