Changes in Electronic Structure of the Electrochemically Li-Ion Deintercalated LiNiO2 System Investigated by Soft X-Ray Absorption Spectroscopy

Published

December 7, 2006

Author(s)

W S. Yoon, Kyung Y. Chung, James McBreen, Daniel A. Fischer, Xiao-Qing Yang

Abstract

The electronic structures of Li1-xNiO2 system after electrochemically delithiated to various x values have been investigated using soft X-ray absorption spectroscopy (XAS) for oxygen K-edge and Ni LII,III-edge. By comparing the O K-edge XAS spectra of Li1-xNiO2 electrode collected simultaneously by the partial electron yield (PEY) mode and florescence mode (FY), it was found that the surface electronic structure of Li1-xNiO2 electrode is different from the bulk. Therefore, if the PEY mode, which is a surface-sensitive technique, is used alone, the reliability of the results is limited to the surface structures only. Ni LII,III-edge XAS results of Li1-xNiO2 electrode at different charge states, in both the FY and PEY modes, show that Ni2+ ions at the surface are mostly oxidized to Ni3+ ions during Li deintercalation, whereas the process in the bulk is the oxidation of Ni ions from Ni3+ to Ni4+.

Citation

Journal of Power Sources

Volume

163

Issue

1

Pub Type

Journals

Keywords

Lithium rechargeable batteries, NEXAFS, XAS

Citation

Yoon, W. , Chung, K. , McBreen, J. , Fischer, D. and Yang, X. (2006), Changes in Electronic Structure of the Electrochemically Li-Ion Deintercalated LiNiO₂ System Investigated by Soft X-Ray Absorption Spectroscopy, Journal of Power Sources (Accessed January 2, 2025)