REcycling Li/Li ion batteries: a new concept bAsed on soluBility et (electro)chemical vaLorization of materials in moltEn salts – RELIABLE

(i) Selection of the molten salt chemistry. Molten salts encompasses a large family featuring different physico-chemical properties. It is necessary to evaluate the most suited molten salt having the dual properties of being able to solubilize the electrode material, decompose organic compounds that are present in the battery and allow recovering metals.
(ii) Study of the liquid structure of the molten salts and the speciation of metallic species. Knowledge on the metal ion speciation in molten salts is of paramount importance since it dictated their physico-chemical properties such as the potential at which metals are reduced. This study will be performed by mean of Synchrotron based experiments and molecular dynamic simulations.
(iii) Analysis of the degradation of the organic compounds of the batteries in the molten salts. Decomposition mechanisms of the binder will be investigated.
(iv) Metals recovery. Metals can be recover by means of electrodeposition or precipitation.

- Development of a new setup for the in situ X-ray absorption spectroscopy investigation of the dissolution of cobalt from cathode into oxidizing molten salts (carbonates, hydrogenosulfates and hydroxides)
- Proposition of a selective route to recover cobalt from cathode battery materials using hydrogenosulfates.

The tools for the understanding of lithium battery cathode materials dissolution in molten salts have been developed. It will be now possible to characterize the mechanisms of oxidation state evolution of metals and their dissolution in selected molten salts. It will help the design of the most suitable method to recover critical metals from the wastes.
A route using hydrogenosulfate has bee evaluated on pure compound. It will now important to test the method on black mater (residue of first step of battery recycling process).
The degradation/recycling of the organic mater contained in battery has to be investigated. In addition, its impact on the metals recovery has to be evaluated.

RELIABLE treats the Lithium Battery recycling using pyrochemistry. The goal is to use molten salts as solvent in order to dissolve batteries, particularly cathodes, and to selectively recover every metallic species. Eutectic mixtures of molten carbonates will be used but other oxidizing salts will be also investigated. The project aims to build the basic knowledge for the development of a process and a laboratory pilot. In a first step, the solubility of metals and their speciation in the bath will be studied in function of several parameters such as oxo-acidity, presence of additional species (phosphate…), etc. In a second step, the recovery ways will be explored, in particular electrodeposition. In this aim, Electrochemical studies will be performed. Finally a laboratory pilot will be proposed.