Cartographies quantitative du lithium : application aux systèmes de stockage électrochimique

The electric vehicle market is today a fast growing market. This induces the development of characterization techniques for the study of batteries materials. More precisely, the imaging of lithium is of paramount importance for the design of electrochemical storage systems and the understanding of the phenomena occurring in these systems during their use.
We propose a thesis work focused on the development of a coupling between LIBS (Laser-Induced Breakdown Spectroscopy) and LIF (Laser-Induced Fluorescence) in order to obtain a new elemental microscopy system. Such system will be able to image quantitatively, rapidly and with high sensitivity, the repartition of lithium into battery materials with a one micrometer lateral resolution. This new system has a targeted resolution one order of magnitude better than the state-of-the-art. The PhD fellow will have to build the LIBS-LIF coupling from existing elements (lasers, optics, spectrometer, detector, sample stage, control software). He/she will have to study the relaxation and re excitation processes in the plasma by varying the acquisition parameters (lasers flux, inter-pulse delay, detection delay and detection gate, …) in order to optimize the gain in emissivity brought by the second laser pulse. He/she will have to make out calibration curves in order to obtain a quantitative analysis. He/she will show the contributions and measure the performance of the coupling by characterizing several Li-ion batteries systems. The Li-ion systems under study will contain aged batteries in cycling or calendar conditions, composed of materials for new battery generations (anode with silicon doped graphite, cathodes with blend).
 

Mots-clés : Spectroscopie, Laser, Imagerie, Batteries, Li-ion