Ellen Phiddian
Cosmos science journalist
A new study has found that reusing lithium-ion battery materials has a much lower environmental impact than mining the raw material – particularly if it’s done with renewable energy.
The study, published in Nature Communications, found that recycling batteries emits less than half the greenhouse gases associated with mining and roughly a quarter of the energy and water.
Some practices could reduce the impact of recycling even further – such as changing electricity sources, and recycling batteries into mixed-metal products rather than specific battery-grade materials.
“This study tells us that we can design the future of battery recycling to optimise the environmental benefits. We can write the script,” says co-author William Tarpeh, a chemical engineer at Stanford University in the USA.
The researchers compared the footprints of mining battery materials to those of a major battery recycling company in the USA.
They found that electricity use was the most significant contributor to recycled batteries’ environmental footprint. Transport and extraction, meanwhile, played a much larger role for conventionally made (mined) batteries.
“A battery recycling plant in regions that rely heavily on electricity generated by burning coal would see a diminished climate advantage,” says study co-author Samantha Bunke, a PhD student at Stanford.
“On the other hand, fresh-water shortages in regions with cleaner electricity are a great concern.”
A lot of battery recycling is done via pyrometallurgy, which requires very high temperatures and therefore high electricity. The recycling plant the researchers used for analysis, Redwood Materials, used a more efficient process called “reductive calcination”, which doesn’t require fossil fuels.
But the team points out that battery recycling is improving with more research.
“Other pyrometallurgical processes similar to Redwood’s are emerging in labs that also operate at moderate temperatures and don’t burn fossil fuels,” says study co-author Xi Chen, a postdoctoral scholar at Stanford during the time of research and now at City University of Hong Kong.
“Every time we spoke about our research, companies would ask us questions and incorporate what we were finding into more efficient practices.
“This study can inform the scale-up of battery recycling companies, like the importance of picking good locations for new facilities.”
