Contribution of X-ray Photoelectron Spectroscopy to the Study of the Electrochemical Reactivity of CoO toward Lithium

The positive attributes of X-ray photoelectron spectroscopy to the field of battery research is illustrated through the study of reaction mechanisms involved during the electrochemical reduction/oxidation of a metal oxide (MO) electrode vs Li. Through the acquisition and interpretation of various (Co 2p, Li 1s, O 1s, and C 1s) XPS spectra during the charge and discharge of a CoO/Li battery, we could confirm the reversibility of the CoO → Co conversion reaction process involving the reversible formation/decomposition of CoO and Li2O together with the reversible growth of an organic layer. More importantly, such measurements suggested that the organic polymer could contain, among others, oligomer chains of poly(ethylene oxide) (CH2CH 2O)n.