Effect of recycling conditions on the physico-chemical properties of NMC electrodes: towards an advanced multi-scale characterization

To meet environmental objectives, one of the main levers is the electrification of the vehicle fleet. This will lead to a sharp increase in the production of Li-ion batteries over the next decade. For environmental and geostrategic reasons, recycling of these batteries in Europe will have to be implemented. Conventional methods for recovering metals exist, but they are very energy-intensive and do not allow the active materials to be kept in their original state. Direct recycling of active materials therefore seems a promising alternative. However, the processes still need to be developed. This thesis proposes to study the impact of short-loop recycling processes on the morphological, textural, surface and usage properties of mixed oxides of lithium, nickel, cobalt and manganese (NMC). These materials are used in the positive electrodes of commercial Li-ion batteries and store lithium by intercalation of lithium ions between the oxygen planes of their structure. Each unitary step of recycling (grinding, thermal treatment, ...) has an impact on the NMC physico-chemical properties, thus modifying their properties of use. This thesis proposes to study samples produced at a laboratory scale, representative of unitary stages of recycling of NMC phases in order to:
•    Develop a multi-technique analytical methodology to characterize these materials from the different unitary stages. We will be particularly interested in their structure (lithium intercalation capacity) and their surface (mobility barrier). The student will thus be led to use advanced techniques such as XRD, XPS or high resolution TEM. Experiments at synchrotron will also be envisaged. 
•    To make the link between the impact of the unit steps on the microstructural properties and the properties of use (insertion capacity, mobility of lithium).

Keywords: Battery, recycling, NMC, characterization, X-ray diffraction, diffusion, lithium

• Academic supervisor    Dr, SORBIER Loïc, IFPEN, https://orcid.org/0000-0001-5591-9848
• Doctoral School    206 - Ecole doctorale Chimie, Procédé, Environnement
• IFPEN supervisor    Dr HUMBERT Séverine, département Physique et analyse, severine.humbert@ifpen.fr, https://orcid.org/0000-0003-1884-2858
• PhD location    IFP Energies nouvelles, Lyon, France
• Duration and start date    3 years, starting in fourth quarter 2023
• Employer    IFP Energies nouvelles, Lyon, France
• Academic requirements    University master’s degree in chemistry or material engineering
• Language requirements    Fluency in English, willingness to learn French
• Other requirements    Strong knowledge of characterization techniques is required