Simon Coudray PhD defense
Glasses and Ceramics (V&C) team
Abstract
This PhD work focuses on the development of chalcogenide glasses optical fibers for monitoring chemical reactions in batteries using infrared spectroscopy. Lithium-ion batteries undergo numerous chemical reactions involving molecular species whose vibrational signatures can be identified using infrared spectroscopy. In this context, Te20As30Se50 tapered glass fibers were reproducibly fabricated to improve sensor sensitivity. The performance of these fibers was then evaluated in electrolytes and in various battery systems. New Ge–As–Se glass compositions have been developed to increase the operating temperature of the fibers and enable the monitoring of thermal runaway in batteries. In a second step, this thesis focused on the development of an optoelectrochemical sensor. This sensor was fabricated by depositing a conductive ITO layer onto Te20As30Se50 glass fibers. The fiber was then used as a working electrode, in particular to investigate a Prussian blue cathode material in aqueous and organic media. Finally, microstructured exposed-core fibers and step-index fibers were developed. Additive manufacturing was used to produce the preforms. Step-index fibers were also produced using the double-crucible method. 3D printing has demonstrated its great potential for creating new sensor geometries that allow the integration of a polymer to protect the fiber and improve its mechanical properties.
Jury
Jean-Christophe Sangleboeuf, Professor, IPR, University of Rennes / Examiner
Wilfried Blanc, CNRS Research Director, INPHYNI, University of Côte d’Azur / Examiner
François Ozanam, Research Director, PMC, École Polytechnique / Reviewer
Charlotte Mouravieff, CNRS Researcher, CSE, Collège de France / Reviewer
Xiang-Hua ZHANG, CNRS Research Director, ISCR, University of Rennes / PhD Director
Catherine BOUSSARD-PLÉDEL, Research Engineer, ISCR, University of Rennes / PhD Co-Director