IEEE Spectrum reports on a research team that has created a new method for recycling the environmentally risky chemicals used in lithium-ion batteries – the kind of batteries used in cellphones, laptops, and electric cars. The technique, surprisingly, produces batteries that are actually more efficient than those made from newly-mined lithium:
“In general, people’s impression is that recycled material is not as good as virgin material,” says Yan Wang, a professor of mechanical engineering at Worcester Polytechnic Institute. “Battery companies still hesitate to use recycled material in their batteries.”
A new study by Wang and a team including researchers from the US Advanced Battery Consortium (USABC), and battery company A123 Systems, shows that battery and carmakers needn’t worry. The results, published in the journal Joule, show that batteries with recycled cathodes can be as good as, or even better than those using new state-of-the-art materials.
The team tested batteries with recycled NMC111 cathodes, the most common flavor of cathode containing a third each of nickel, manganese, and cobalt. The cathodes were made using a patented recycling technique that Battery Resourcers, a startup Wang co-founded, is now commercializing.
The recycled material showed a more porous microscopic structure that is better for lithium ions to slip in and out of. The result: batteries with an energy density similar to those made with commercial cathodes, but which also showed up to 53% longer cycle life.
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Their technology involves shredding batteries and removing the steel cases, aluminum and copper wires, plastics, and pouch materials for recycling. The remaining black mass is dissolved in solvents, and the graphite, carbon and impurities are filtered out or chemically separated. Using a patented chemical technique, the nickel, manganese and cobalt are then mixed in desired ratios to make cathode powders.
A few other researchers, and outfits such as the ReCell Center, a battery-recycling research collaboration supported by the U.S. Department of Energy, are also developing direct recycling technology. But they likely will not be producing high volumes of recycled cathode material any time soon.
Battery Resourcers, meanwhile, is already selling their recycled materials to battery manufacturers at a small scale. The company plans to open its first commercial plant, which will be able to process 10,000 tons of batteries, in 2022.
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You can read more about the lithium-cathode-recovery research here, in the journal Joule.