Electrochemical Mechanisms during Lithium Insertion into TiO0.6 S 2.8 Thin Film Positive Electrode in Lithium Microbatteries

Abstract

Amorphous thin films were prepared by radio frequency magnetron sputtering from target under pure argon atmosphere. Two complementary techniques, X-ray photoelectron spectroscopy and X-ray absorption spectroscopy, were used to investigate the local and electronic structure of the as-prepared sample and to study the electrochemical mechanisms occurring during the first cycle. The results exhibit that the as-prepared thin film is close to bulk [which may be viewed as with regard to the local and electronic structure. An electrochemical characterization of the film was performed. Upon lithium insertion, sulfur is first involved in the electrochemical reduction, followed by titanium. The reduction of to is concomitant with the elongation of the distance between the two sulfur ions of the disulfide pair. At the end of the charge, the electrochemical processes appear to be reversible. This study clearly evidences the major contribution of sulfur atoms beside titanium. © 2004 The Electrochemical Society. All rights reserved.