Jiakai Zhang a, Gisele Azimi a,b,*
a Laboratory for Strategic Materials, University of Toronto, Department of Chemical Engineering and Applied Chemistry, 200 College Street, Toronto, Ontario, M5S 3E5,
b Department of Materials Science and Engineering, University of Toronto, 184 College Street, Toronto, Ontario, M5S 3E4, Canada
The widespread utilization of lithium-ion batteries (LIBs) will lead to multimillion tons of end-of-life LIBs. The batteries comprise high content of valuable metals including lithium, cobalt, nickel, and manganese; hence, their recycling is imperative. This study develops a supercritical fluid extraction process using supercritical CO2 solvent with tributyl phosphate–nitric acid and hydrogen peroxide adduct to recover the four metals from the LIBs of electric vehicles. A full factorial design of experiment is utilized to determine the effect of temperature, pressure and adduct to solid ratio on the extraction. The extraction is optimized using empirical models, leading to 90% metal extraction. The addition of hydrogen peroxide improves the extraction by reducing metals to more soluble forms in supercritical CO2. A systematic investigation is performed to elucidate the process mechanism. The developed process can help management of end-of-life LIBs, conserve of natural resources, and promote the circular economy.