Electric vehicles are driving the initiative to reduce greenhouse gas emissions in the transportation sector. However, GHG emissions from current lithium-ion battery recycling processes can undo the gains from electric vehicles.

Existing lithium-ion battery recycling processes are designed for the relatively low size and volume of consumer electronic batteries such as AAs and AAAs.

However, with the automotive manufacturing industry committing themselves to all electric or hybrid-electric product lines in the coming years, the market will be flooded with new lithium-ion batteries, necessitating a completely different approach to battery recycling.

Having reviewed various battery recycling processes, Jay Whitacre, director of the Wilton E. Scott Institute for Energy Innovation and professor of materials science and engineering and engineering and public policy, and Rebecca Ciez, a postdoctoral fellow at Princeton University and former student of Whitacre, have laid out a path forward for the re-use of these lithium-ion batteries.

According to Ciez, automakers are also interested in recycling as a potential source of low-cost material that can be remanufactured into new battery packs.

Comparing a direct cathode recycling process to other recycling processes in terms of GHGs and energy consumption, the researchers found that this method of battery recycling keeps the cathode materials intact, allowing their re-use in future batteries. While all lithium-ion batteries use lithium to carry the charge, their cathodes, which store the lithium ions when the battery is discharged, can be made from materials such as nickel, manganese or cobalt.

Ciez explains that they focused their analysis on specific lithium-ion formulations that are most common in today's electric vehicles and found that for cathodes containing metals such as nickel, manganese and cobalt, direct cathode recycling can reduce the greenhouse gas emissions associated with manufacturing new batteries from the materials.

However, the researchers say technology needs to be supported by policy to reduce GHG emissions through battery recycling. Policies for lithium ion battery recycling must both encourage collection of automotive lithium-ion batteries, and mandate that recycling processes offer net reductions in GHG emissions.

Therefore, if technology and policy can work in tandem to implement recycling processes for these cathode materials, lithium-ion batteries will help electric vehicles emit fewer GHGs, both at the tailpipe, and the manufacturing plant.