Quantitative microscopy of lithium by LIBS in battery - pHD position between ILM and IFPEN

The electric vehicle and electric battery markets show a tremendous growth. Understanding the microscopic phenomena occurring in the batteries, mostly lithium-based, is of paramount importance to further improve their performance. Hence, characterizing and imaging these systems down to the microscopic scale is key and current techniques have to be pushed forward.

We propose a thesis project aiming to perform rapid, highly sensitive and quantitative images of the repartition of lithium into battery materials with a one micrometer lateral resolution. The work will, in a first step, be 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. 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 experimental 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. In a second step he/she will have to render the experiment able to perform quantitative analysis. He/she will then show the contributions and measure the performance of the coupling by characterizing several Li-ion batteries systems, that he/she will have prepared. 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).

The candidate will conduct its PhD at the Optolyse platform within Institut Lumière Matière in the scope of the ANR project Micro-Q-Li in collaboration with IFP Energies nouvelles.