Development and characterization of a water-based end-of-life recycling process of lithium ion batteries

by Lorena Toledo (presenting author)1, Rolf Widmer1, Olivier Groux2

1: Empa Swiss Federal Laboratories for Materials Science and Technology; 2: KYBURZ Switzerland AG

 

‘Systems Thinking’ is an approach to help understand complexity and identify system leverage points and is often recognised as being critical to delivering a Circular Economy (CE) – yet little research has been presented that integrates CE concepts, causes and effects within this holistic approach.

The lack of proper disposal of spent lithium-ion batteries (LIBs) and the increasing uptake of LIBs, particularly from the electric transportation industry pose a challenge for end-of-life waste management. Thereby, the need to develop an adequate recycling process for spent LIBs is of high importance due to their impact on the environment, energy conservation and resource scarcity.

KYBURZ Switzerland AG develops and produces high quality electric vehicles (EV) for the postal service, industrial sector and private market. In total, KYBURZ uses 2500 lithium iron phosphate (LiFePO4) batteries per year to produce a fleet over 22000 EV. This type of LIBs contains valuable materials such as copper, aluminum, graphite, transition metal oxides and organic electrolytes with lithium salts.

Together with KYBURZ, we develop an in-house recycling process for LiFePO4 batteries that is both environmentally friendly and cost-efficient in compliance with legal and safety requirements. The aim of the project is to find a close loop path to reuse recycled materials from spent LiFePO4 batteries to produce new ones for EV manufactured by KYBURZ.

Spent LiFePO4 batteries are first collected, discharged and then manually dismantled. The separation of the electrode materials consists of a carbonate bath to dissolve the lithium salt (LiPF6), followed by a water bath to separate the metal oxide from the aluminum foil as well as the graphite from the copper foil. As future work, selective leaching and/or calcination processes will be performed and optimized to recover lithium, metal oxide and graphite. Recovered materials are characterized by Energy Dispersive X-Ray Spectroscopy (EDX), Scanning Electron Microscope (SEM) and Inductively Coupled Plasma Spectroscopy (ICP). These analyses allow us to demonstrate that the products obtained can be used as secondary raw materials to produce new batteries.