A new process is optimized and presented for the recovery and regeneration of LiFePO4 from spent lithium-ion batteries (LIBs).

As an indispensable part of lithium-ion batteries (LIBs), closed-loop recycling, reusing the electrolyte from spent LIBs, has not yet been fulfilled experimentally. Herein, this paper presents a LIB electrolyte recycling approach which consists of supercritical CO2 extraction, resin, and molecular sieve purification and components supplements. The resultant electrolyte exhibited a high ionic conductivity of 0.19 mS·cm–1 at 20 °C, which was very close to a commercial electrolyte with the same composition. Moreover, the electrolyte was also electrochemically stable up to 5.4 V (vs Li/Li+) in the linear sweep voltammetry (LSV) measurement. The application potential of reclaimed electrolyte was demonstrated by Li/LiCoO2 battery presenting the initial discharge capacity of 115 mAh·g–1 with a capacity retention of 66% after 100 cycles at 0.2 C. This investigation is a crucial break for electrolyte recycling and opens a bright route toward realizing closed-loop LIB recycling.

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 À1 . Under these conditions, the extraction yield was 85.07 AE 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.