Recovery of NMC-lithium battery black mass by microwave heating processes

The exceptional microwave absorption capabilities of carbon-based materials make them highly effective for facilitating various chemical reactions, such as synthesis, reduction, exfoliation, doping, and decoration. In this study, we applied microwave irradiation to the thermochemical treatment of spent nickel manganese cobalt (NMC622) lithium-ion batteries, obtained as a mix of the cathode and the anodic graphite. This approach significantly accelerated the chemical reactions, leveraging carbon's robust ability to absorb microwave energy. As a proof-of-concept, we demonstrated that within just 5 min, the carbothermic reduction reactions in the black mass facilitated the formation of water-soluble Li2O, and enhanced the solubility of Co, Mn, and Ni in a weak acid. More than 90% of Li and 87% of Mn are recovered. This method, which bypasses the need for cathodic and anodic separation, presents a promising new approach for recovering strategic metals from spent lithium-ion batteries.