Comprehensive X-ray Photoelectron Spectroscopy Study of the Conversion Reaction Mechanism of CuO in Lithiated Thin Film Electrodes

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• 作者：Lucile Martin ; Herv茅 Martinez ; Delphine Poinot ; Brigitte Pecquenard ; Fr茅d茅ric Le Cras
• 刊名：The Journal of Physical Chemistry C
• 出版年：2013
• 出版时间：March 7, 2013
• 年：2013
• 卷：117
• 期：9
• 页码：4421-4430
• 全文大小：479K
• 年卷期：v.117,no.9(March 7, 2013)
• ISSN：1932-7455

文摘

The course of the conversion reaction during the electrochemical insertion/deinsertion of lithium in CuO thin film electrodes was surveyed by cyclic voltammetry (CV) and X-ray photoelectron spectroscopy (XPS). The electrochemical processes were studied through the comprehensive acquisition and interpretation of XPS and Auger spectra (Cu 2p, O 1s, Cu LMM) recorded at different stages of the first cycle of a Li/CuO cell. The reduction process consisting of three main steps leads successively to Cu⁺ and Cu⁰ and involves a Li₂O₂ peroxide type phase as an intermediate, whereas Li₂O is the main lithiated oxide at the end of the discharge. Only the two last steps appear reversible in charge. No evidence of Cu²⁺ was found at the end of the charge at 3.5 V/Li⁺/Li, showing the irreversibility of the first step in our experimental conditions. Complementary XPS depth profile analyses were performed to check the evolution of the active material composition over the thickness of the electrode.