Efficient and mild: recycling of used lithium-ion batteries
© Wiley-VCH, re-use with credit to 'Angewandte Chemie' and a link to the original article.
Lithium-ion batteries (LIBs) provide our portable devices like
tablets and mobiles—and increasingly also vehicles—with power. As the
share of volatile renewable energy needing electricity storage
increases, more and more LIBs are needed, lithium prices rise, resources
dwindle, and the amount of depleted batteries that contain toxic
substances increases. In the journal Angewandte Chemie, researchers introduce a novel approach for the recovery of lithium from used LIBs.
The recycling of LIBs is a difficult undertaking. The recovery of
lithium of a quality high enough to be used again is complicated and
expensive. Most recycling processes are targeted at extracting the
lithium from cathodes (where most of the lithium in discharged batteries
is located). However, it then precipitates out together with other
metals contained in the cathode and must be painstakingly separated.
Extraction from the anodes, which consist primarily of graphite, is
significantly more efficient and can be carried out without discharging
the battery beforehand. Because of their high reactivity, however, the
risk of fires and explosions is high if the anodes are leached out with
aqueous solutions, as is usual. These reactions release large amounts of
energy and may produce hydrogen.
A team led by Yu-Guo Guo and Qinghai Meng at the Institute of
Chemistry of the Chinese Academy of Sciences (ICCAS) and the University
of Chinese Academy of Sciences (UCAS) has now developed an alternative
method that avoids these problems. Instead of water, they use aprotic
organic solutions to recover lithium from anodes. Aprotic substances
cannot release any hydrogen ions, so no hydrogen gas can form.
The solutions consist of a polycyclic aromatic hydrocarbon (PAH) and
an ether as the solvent. Certain PAHs can take up a positively charged
lithium ion from the graphite anode together with one electron. Under
mild conditions, this redox reaction is controlled and very efficient.
With the PAH pyrene in tetraethylene glycol dimethyl ether, it was
possible to dissolve the active lithium from the anodes almost
completely.
An additional advantage is that the resulting lithium-PAH solutions
can be used directly as reagents, for example, in adding lithium to new
anodes in preprocessing or in regenerating spent cathodes. The
PAH/solvent system can be varied to optimize it for the material being
treated.
This recovery process is efficient and inexpensive, reduces safety
risks, avoids waste, and opens new prospects for the sustainable
recycling of lithium-ion batteries.
(2623 characters)
About the Author
Dr. Yu-Guo Guo has
been a full Professor of Chemistry at the Institute of Chemistry,
Chinese Academy of Sciences (CAS), since 2007. He is leading a research
group with research interests focused on energy materials and
electrochemical energy-storage devices, such as Li-ion, Li-metal, Na-ion
batteries, and solid-state batteries.
Copy free of charge—we
would appreciate a transcript/link of your article. The original
articles that our press releases are based on can be found in our online pressroom.