Supercritical CO2 extraction behavior of electrolyte solvents from Li-ion battery black mass

Journal article, 2025

Electrolyte recovery from spent Li-ion batteries remains a significant challenge in the current recycling process. Li-ion battery waste streams containing electrolyte residues are classified as hazardous waste and entail a financial and workplace safety burden for the recycling industry. Recent studies show the potential use of supercritical CO2 extraction for the recovery of electrolyte solvents. In this study, the extraction behavior of electrolyte solvents from Li-ion battery black mass using supercritical CO2 process under pressures of 100 and 140 bar at 40 degrees C was investigated. The extraction yield of dimethyl carbonate, ethyl methyl carbonate, and diethyl carbonate exceeded 99 % at both pressures. Ethylene carbonate, biphenyl, and propylene carbonate were successfully extracted with an extraction yield exceeding 95 % using 140 bar and 40 degrees C. The extraction rates of biphenyl, ethylene carbonate and propylene carbonate at 140 bar and 40 degrees C in the linear extraction regime of the extraction curve were determined to be 0.18 mg/g CO2, 1.9 mg/g CO2 and 0.4 mg/g CO2, respectively. The research demonstrates that supercritical COQ processing is a highly promising method not only for recycling electrolytes but also for mitigating the hazardous risks associated with battery waste.