Scientists at Oak Ridge National Laboratory have developed a solvent that results in a more environmentally friendly process to recover valuable materials from used lithium-ion batteries; supports a stable domestic supply chain for new batteries; and keeps old ones out of landfills. A paper on the work is published in the journal ACS Sustainable Chemistry & Engineering.
Spent batteries are typically broken down using smelting—an expensive, energy-intensive process that releases toxic gas. The ORNL-developed alternative is a wet chemical process using triethyl phosphate (TEP) to dissolve the binder material that adheres cathodes to metal foil current collectors in Li-ion batteries.
Electrochemically active materials were separated from cathode scraps collected at the manufacturing step of electrodes through a solvent-based separation method without jeopardizing their physical characteristics, crystalline structure, and electrochemical performance. We found that the recovered aluminum foils were clean without any sign of corrosion and that the polymeric binder could be recovered via a non-solvent-induced phase separation. Additionally, recovery of cathode materials from spent cells was achieved using refined separation parameters based on the recycling of cathode scraps. It is anticipated that this green solvent-based separation for cathode recovery will attract significant interest by the lithium-ion battery manufacturing and recycling communities.—Bai et al.
The result is efficient recovery of cobalt-based cathodes, graphite and other valuable materials such as copper foils that can be repurposed in new batteries.
With this solvent, we’re able to create a process that reduces toxic exposure for workers and recovers valuable, undamaged, active NMC [nickel-manganese-cobalt] cathodes, clean metal foils and other materials that can be easily reused in new batteries.—ORNL’s Ilias Belharouak
Yaocai Bai, Rachid Essehli, Charl J. Jafta, Kelsey M. Livingston, and Ilias Belharouak (2021) “Recovery of Cathode Materials and Aluminum Foil Using a Green Solvent” ACS Sustainable Chemistry & Engineering doi: 10.1021/acssuschemeng.1c01293