Recycling lithium-ion batteries to recover their critical metals has significantly lower environmental impacts than mining new metals.
A Stanford University lifecycle analysis found that recycling emits less than half the greenhouse gases of mining and refining the metals - and about a quarter of the water and energy of mining new metals.
Material for lithium-ion battery recycling comes from two main streams: scrap material from manufacturers and end-of-life batteries, from which lithium, nickel, cobalt, copper, manganese, and aluminium is extracted.
Recycling scrap has the highest environmental benefit with only 19% of the greenhouse gas emissions of mining and processing, 12% of the water use, and 11% of the energy use, and also leads to less air pollution from soot and sulphur.
Most of the study’s data for battery recycling came from Redwood Materials in Nevada — North America’s largest industrial-scale lithium-ion battery recycling facility — which the researchers said benefits from a cleaner energy mix including hydropower, geothermal, and solar.
The environmental impact of recycling is heavily dependent on the location and electricity source; battery recycling plants in regions that rely heavily on electricity generated by burning coal would see a diminished climate advantage, they noted.
“The analysis revealed that refining end-of-life lithium-ion batteries into battery-grade cathode materials exhibited lower environmental impacts than conventional refinement of mined materials, mixed salts products were more beneficial for circular refinement, and the source of input electricity is the principal factor governing circular refinement environmental impacts,” the paper published in Nature Communications said.
Transportation is also a crucial factor: 80% of the global supply of cobalt is mined in the Democratic Republic of the Congo, and 75% of the cobalt supply for batteries travels by road, rail, and sea to China for refining. Most of the world’s lithium is mined in Australia and Chile and also travels to China for processing. Meanwhile, for battery recycling, used batteries and scrap which must be collected and delivered to the recycler.
The researchers calculated that the metals in a battery if conventionally mined and refined will travel about 35,000 miles (57,000 kilometres) - the same as going around the world one and a half times. In contrast the total transport for a used cell phone or an EV battery could be as low as 140 miles (225 kilometres) in future, based on the optimal locations for future refining facilities in the US.
Industrial-scale battery recycling is growing, but not quickly enough, according to the researchers while the U.S. now recycles about 50% of lithium-ion batteries, it has recycled 99% of lead acid batteries for decades. Used lithium-ion batteries contain materials with up to 10 times higher economic value.
Getting that percentage up will create a recycling system from collection to processing back into new batteries with minimal environmental impact, they said, and for battery manufacturers to consider recyclability more in their future designs, too.
“While refining end-of-life batteries is more environmentally intensive than refining [lithium-ion battery scrap]… it is critical to improve the technologies for recycling energised batteries when a larger volume of end-of-life batteries becomes available from EVs,” the paper said.
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- Lithium-ion batteries: New recycling method restores spent cathode materials
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