Due to their lifespan, massive flows of Lithium-ion batteries are currently being generated. In this context, the European Union imposes in terms of recycling of at least 70% of the materials contained in batteries with thresholds for reincorporation of recycled metals into Li, Ni and Co between 10 and 20% from 2035. A battery is made up of four main elements: a cathode, an anode, a polymeric binder and an electrolyte. Due to the lack of standardization, its recycling is a delicate and dangerous operation due to electrical, chemical and thermal runaway risks. Current recycling routes, implementing pyro/hydrometallurgy stages, require high energy flows or high volumes of mineral acids. The thesis project aims to study a hydrothermal recycling process between 150 and 300°C, innovative and environmentally friendly, of end-of-life battery electrodes, with the aim of selectively recovering the metals of interest ( objective extraction yield of Li, Co, Ni and Mn greater than 95%). In a first step, this process will be implemented in batch mode on representative production scraps and coupled with precipitation and solid-liquid extraction steps in order to recover the metals of interest. Subsequently, this leaching treatment will be considered in semi-dynamic mode on these scraps. Its implementation makes it possible to control the oxidoreductive nature of the environment and the uncorrelated control of pressure and temperature, in order to sequentially extract the metals. Modeling approaches aimed at determining the rate-limiting stage of metal recovery and defining the appropriate temperature by calculating thermodynamic equilibrium constants of precipitation/complexation. An energy balance will be implemented in order to evaluate and compare these two paths with a view to studying the complete life cycle of the process.
The thesis will take place at Marcoule center located 30 minutes from Avignon, in a multidisciplinary team with skills in the field of implementing recycling processes using supercritical fluids and/or fixed bed adsorption. The desired candidate is an engineer/Master holder with a process or chemical engineering profile and desired skills in analytical chemistry and inorganic chemistry. The candidate will gain initial experience in battery recycling, which constitutes one of the major issues linked to the circular energy economy. Depending on the direction of the thesis, he may pursue his career in academia or in the battery production or recycling industry.