A chemical injection can restore spent lithium-ion batteries to working order again. The one-step process could reduce waste and boost the supply of batteries needed for fleets of electric vehicles.
As batteries age, they lose some of the charged particles that let them store energy, which reduces their power-holding capacity. Injecting certain chemicals can reverse this type of degradation 鈥� although it does not fix structurally damaged batteries 鈥� according to researchers affiliated with the automotive giant Toyota Group. Restoring lithium-ion batteries could extend their useful lifetimes, allowing them to be reused in electric cars or other devices rather than being discarded or undergoing a complex disassembly and recycling process.
鈥淭he effectiveness of the system was verified not only with small-sized batteries for lab use, but also with large batteries for automotive use,鈥� says at the Toyota Central R&D Labs., Inc. in Japan.
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To achieve this regeneration, Ogihara and his colleagues needed to add more of the particles that enable a battery to store power: positively charged lithium ions and negatively charged electrons. The researchers tested several possible recovery reagents, substances that produce these particles through chemical reactions. Their experiments showed that a recovery reagent based on lithium naphthalenide could boost both types of charged particle and restore 80 per cent of original battery capacity. The renewed capacity lasted through 100 cycles of charging and discharging.
Long-term studies of the restored battery performance are necessary to understand any potential side effects from the chemical injection, says at Imperial College London. She also points out the technique鈥檚 limitations.
鈥淚t鈥檚 only for batteries which have undergone a very specific form of degradation鈥� and that is only useful if you know the history of the battery or can diagnose what state it is in through simple, non-destructive methods,鈥� she says. 鈥淏ut it is useful to have a way to restore at least one stream of batteries.鈥�
The Toyota research group has submitted a patent application for the work. And the idea of restoring used batteries has attracted interest and funding from other companies as well as government bodies such as the US .
鈥淎nything getting us closer to circularity in battery technology 鈥� in particular something that avoids disassembly and reassembly 鈥� is very exciting news,鈥� says at the Massachusetts Institute of Technology. 鈥淚t is likely that this wouldn鈥檛 work for an indefinite number of cycles, so other technologies requiring disassembly will still be necessary. But this seems technologically very promising.鈥�
Joule
