The Li-ion batteries (LIBs) penetration in the automotive market makes more urgent the boosting of zero-waste battery recycling. This can play a crucial role in developing a circular economy through the recovery of critical raw materials (CRMs), as well as non-metallic components back to use. In recent years, the recycling technologies for LIBs entered in a new stage focused on the development of i) advanced pre-treatment processes to separate all the valuable battery components, and ii) more sustainable metallurgical approaches. Compared to the common recycling processes, Supercritical Fluid (SCF) technology is environmentally benign, chiefly if CO2 is used as the SCF (scCO2). This review aims at providing an overview on the current progresses and the open challenges of SCF technology for the treatment of End-of-Life LIBs. The fundamentals of SCF technology process are discussed, providing the reader a brief overview of principles, operation procedures and instrumentation. Thereafter, the main applications in the field of batteries recycling are reviewed, including electrolyte recovery and high-rate extraction of critical metals from the cathode. Finally, a focus is given on the huge innovation potential of scCO2 to separate and reuse the fluorinated binder from the electrode. At present, the binder is burnt in the common recycling processes, leading to hazardous fluorinated gas emissions.

The increasing demand for Lithium-ion batteries (LIBs) in several applications, from consumer electronics to electric vehicles (EVs), has led to a substantial rise in their production, posing serious risks in the supply of critical raw materials (CRMs, e.g.: Li, Ni, Co, and graphite). Additionally, an improper disposal of end-of-life (EoL) batteries can lead to environmental pollution and loss of technological value (e.g., burning of electrolyte and fluorinated binder) stressing the necessity for a sustainable recycling. Current methods involve shredding whole batteries into a black mass, from which the components are separated through pyrometallurgy (energy-intensive) or hydrometallurgy with inorganic acids (potentially harmful to environment and workers). However, a more refined approach to LIBs recycling involves the dismantling and the sorting of their components, allowing for a targeted extraction. Here, a recycling process for spent cathodes is presented, involving the delamination from the current collector and the leaching of the cathode active material (CAM) into the same citric acid (CA) solution; this also enables the recovery of PVDF and Carbon conducting filler as a residue of the leaching. Lastly, the metals recovered as precursors, are used to resynthesize fresh CAM, thus closing the recycling loop.