Exfoliation of Active Materials Synchronized with Electrolyte Extraction from Spent Lithium‐Ion Batteries by Supercritical CO₂

Abstract

Safe and harmless treatment of electrolyte is a critical environment issue for spent lithium‐ion battery recycling; the effective separation of cathode materials from aluminum foil is a key technology for resource utilization. Previous studies have never considered the two as a whole. This study introduced supercritical CO2 technology to realize the integrated treatment of electrolyte removal and cathode material exfoliation. The results indicated that the optimum parameter was obtained at a temperature of 38 °C, a time of 15 min and a pressure of 10 MPa. The peeling efficiency of cathode material from Al foil reached 98.86 wt.%. Mechanism analysis confirmed that the separation of Al foil and cathode material was the result of the weakened adhesion of electrode interface, which can be attributed to the removal of the organic component including carbonate‐based organic solution and organic binder caused by the fluid extraction process.

Comprehensive Technology for Recycling and Regenerating Materials from Spent Lithium Iron Phosphate Battery

“…Currently, pyrolysis, vacuum distillation, supercritical CO 2 extraction, and solvent extraction methods can be used for the disposal of electrolytes (Figure b). For example, Jie et al converted the electrolyte in spent cathode plates into inorganic gases and alkane gases through vacuum pyrolysis; Xu et al efficiently achieved the separation and recycling of DMC and DEC from EC by vacuum distillation; Mu et al introduced supercritical CO 2 extraction technology to realize the treatment of electrolyte removal and cathode material exfoliation. For materials recovery and regeneration, chemical reagents, such as strong acids, are always consumed.…”

Recycling Hazardous and Valuable Electrolyte in Spent Lithium-Ion Batteries: Urgency, Progress, Challenge, and Viable Approach

“…Some articles have been reported about the supercritical CO 2 extraction of electrolyte from spent LIBs. ,,,− Nowak et al successfully extract four aging products (diethyl carbonate, dimethyl-2,5-dioxahexane dicarboxylate, ethylmethyl-2,5-dioxahexane dicarboxylate, and diethyl-2,5-dioxahexane dicarboxylate) from the electrolyte by supercritical CO 2 . However, the salt LiPF 6 could only be recovered in traces.…”

“…In addition to the above hazardous property, electrolytes are potential resources if properly treated. The Li-based salts in the electrolyte are high-quality Li resources for recycling. − Besides, the flammable and volatile carbonate solvents can be collected and reused as other fuels. On the other hand, the demand and the price of electrolyte are also increasing with the huge production of LIBs.…”

Low‐temperature performance optimization of LiFePO4‐based batteries

“…17 In the production process for a LiFePO 4 electrode, the aluminum foil collector in the cathode usually needs to be pretreated to increase the charge-transfer rate between the electrode active material and collector. [18][19][20][21] It is a breakthrough technological innovation to use functional coating to treat the surface of conductive substrate. At present, the main technical route is to evenly pre-coat conductive carbon nanolayers (such as conductive carbon black or graphene) on both sides of the aluminum foil.…”

“…In the production process for a LiFePO 4 electrode, the aluminum foil collector in the cathode usually needs to be pretreated to increase the charge‐transfer rate between the electrode active material and collector 18–21 . It is a breakthrough technological innovation to use functional coating to treat the surface of conductive substrate.…”