Electrolyte Recovery from Spent Lithium-Ion Batteries Using a Low Temperature Thermal Treatment Process

Electrolyte recovery is seldomly considered in state-of-art lithium-ion battery recycling methods but rather evaporates and decomposes uncontrolled during the pre-treatment steps. However, controlled and safe removal of the electrolyte is inevitable and of high importance to the recycling industry to min-imize the environmental impact of the recycling processes by preventing severe threats produced by the inflammable, toxic and hazardous components of the electrolyte. This study investigated the effects of temperature and process time of a low temperature thermal treatment process on electrolyte recovery. The process exhaust gases and recovered products were analyzed by In-Situ Fourier-transform infrared spectroscopy (FT-IR) and gas chromatography-mass spectrometry (GC-MS) to determine the effective-ness of the significant process parameters. The results show that the electrolyte solvents, which are dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), and ethylene carbonate (EC), were successfully recovered for 80 minutes of processing time at 130 degrees C. The LiPF6 decomposition products hydrogen flu-oride (HF) and phosphoryl fluoride (POF3) were detected in the exhaust gas stream and recovered as acidic solutions. Thermal treatment below 150 degrees C is a promising approach for the recovery of the elec-trolyte solvents prior to the metal recycling stage due to its simplicity, feasibility, and environmental benefit.(c) 2022 The Authors. Published by Elsevier B.V. on behalf of The Korean Society of Industrial and Engi-neering Chemistry. This is an open access article under the CC BY license (http://creativecommons.org/ licenses/by/4.0/).