Formation of SEI on Cycled Lithium-Ion Battery Cathodes: Soft X-ray Absorption Study

Published

January 1, 2002

Author(s)

Mahalingam Balasubramanian, H S. Lee, X Sun, Xiao-Qing Yang, A R. Moodenbaugh, James McBreen, Daniel A. Fischer, Ziwen Fu

Abstract

The formation of a solid electrolyte interface (SEI) on LiNi_0.85Co_0.15O₂ cathodes from lithium-ion cells cycled at 40EC and 70EC was observed and characterized using soft x-ray absorption spectroscopy (XAS). XAS measurements were made in the energy region between 500 and 950 eV, encompassing the Ni and Co L_3- and L_2-edges and at the K-edges of O and F. Measurements, obtained in the total electron yield mode, are surface sensitive, probing to a depth of 5nm . XAS at the F K-edge demonstrates the presence of poly(vinylidene fluoride) (PVdF) in addition to LiF on the surface of cycled electrodes. The results indicate that the PVdF in the cycled electrodes is largely intact and that the LiF comes from decomposition of LiPF6- from the electrolyte. XAS also suggests Fe contamination of cycled cathodes.

Citation

Electrochemical and Solid State Letters

Volume

5 No. 1

Pub Type

Journals

Keywords

battery, electrolyte, lithium-ion, soft x-ray

Citation

Balasubramanian, M. , Lee, H. , Sun, X. , Yang, X. , Moodenbaugh, A. , McBreen, J. , Fischer, D. and Fu, Z. (2002), Formation of SEI on Cycled Lithium-Ion Battery Cathodes: Soft X-ray Absorption Study, Electrochemical and Solid State Letters (Accessed September 20, 2024)