Supercritical CO2 extraction of organic carbonate-based electrolytes of lithium-ion batteries

Abstract

Supercritical fluid extraction (SFE) was applied to reclaim organic carbonate-based electrolytes of spent lithium-ion batteries. To optimize the SFE operational conditions, the response surface methodology was adopted. The parameters studied were as follow: pressure, ranging from 15 to 35 MPa; temperature, between 40 °C and 50 °C and static extraction time, within 45 to 75 min. The optimal conditions for extraction yield were 23 MPa, 40 °C and was dynamically extracted for 45 min. Extracts were collected at a constant flow rate of 4.0 L min⁻¹. Under these conditions, the extraction yield was 85.07 ± 0.36%, which matched with the predicted value. Furthermore, the components of the extracts were systematically characterized and analyzed by using FT-IR, GC-MS and ICP-OES, and the effect of SFE on the electrolyte reclamation was evaluated. The results suggest that the SFE is an effective method for recovery of organic carbonate-based electrolytes from spent lithium-ion batteries, to prevent environmental pollution and resource waste.