Lithium-based transition-metal oxides for battery electrodes analyzed by x-ray photoelectron spectroscopy. IX. LiCoO2

Abstract

X-ray photoelectron spectroscopy (XPS) and x-ray-induced Auger electron spectroscopy were used to analyze untreated LiCoO2 powder obtained from BTR New Energy Materials, Inc. X-ray photoelectron and x-ray-induced Auger electron spectra were obtained using incident monochromatic Al Kα radiation at 0.834 01 nm. A survey spectrum together with Co 2p, O 1s, C 1s, Co 3s, Co 3p, and Li 1s are presented. The spectra indicate the principal core level photoelectron and Auger electron signals and show only minor tin contamination. Making use of the O 1s, Co 3p, and Li 1s lines and neglecting the components related to surface contaminants, XPS quantitative analysis reveals an altered stoichiometry of the air-exposed powder surface of LiCo0.9O1.7.