Extremely efficient deep eutectic solvents for a green approach to metal recovery from spent lithium batteries

LIBs present various critical raw materials (CRMs) (eg Li, Mn, Co, Ni, graphite), not present as massive and primary resources in Europe. The common recovery methods for the extraction of Co, Li, Ni metals are thermal/chemical methods like pyro and hydrometallurgical approaches. They are based on the metal leaching by solvent, supercritical fluid-extraction or chemical precipitation, with the use of strong acids and reducing agents to improve the metal dissolution. However, these processes are highly energy-consuming, require harsh conditions and produce toxic materials. In addition, they do not lead to easily recoverable elements [1]. In our work we are study a green, cheap and safe approach of extraction by using a new type of organic solvents as lixiviant, the Deep Eutectic Solvents (DES). DESs are obtained by simply mixing two safe components (cheap, renewable, and biodegradable), which are capable of forming a eutectic mixture, in our case we combine the acid lactic:choline chloride. We decide to focus the recovery of Li, Ni and Co in a LNC cathode (LiNi0.8Co0.2O2) and the use of the obtained precursor for the realization of a second life cathodes.