PhD in analytical chemistry (M/F) – In situ/operando diagnosis using fibered vibrational spectroscopy

The analysis and interpretation of chemical or biological phenomena is relevant if the study is carried out in conditions as close as possible to real-life conditions, ‘in vitro’ and ‘in vivo’ for living organisms, ‘in situ’ and ‘operando’ for chemical processes or for materials included in devices in operation. Fibered spectroscopic measurements (vibrational spectroscopy) will be developed at IMN under in situ/operando conditions and applied to various energy storage and conversion systems. A detailed understanding of the mechanisms behind the functioning or degradation of materials, a speciality of IMN, will enable their design to be optimised to improve performance.

The development of characterisation methods enabling real-time monitoring of chemical or biological processes and materials in operation is the subject of intensive research (study of energy storage or conversion systems, catalytic systems in operation, (bio)sensors), the “stealthy” nature of these analyses leaving no trace (non-invasive or non-altering) being particularly sought-after. Vibrational spectroscopy is particularly interesting because of the richness of its chemical signature. However, the accessibility of the spectroscopic probe in complex systems (batteries, PAC fuel cells) or in difficult environments (closed reactor, high pressure & temperature, extreme pH) can limit the deployment of these vibrational techniques. Fiber optics can be used to design compact, flexible vibrational probes that are particularly well suited to in situ, operando and even in vivo (endoscopy) applications. Fiber-optic spectroscopy has developed very rapidly in recent years, particularly in the biomedical field, and the associated technical advances have opened up new fields of application, particularly in energy storage (measurements of temperature, refractive index variation, electrolyte composition dynamics and interface composition).

The aim of the thesis work is to develop fibred vibrational spectroscopic measurements under in situ/operando conditions and apply them to the study of the operation of various energy storage and conversion systems: Zn/MnO2 batteries, lithium batteries, PEM/AEM polymer membrane fuel cells (PAC). The electrochemical interfacial phenomena (solvation/de-solvation, formation of passivating layers, local pH variation) and the degradation of PAC polymer membranes limiting the performance of energy storage devices will be studied under operando conditions.