Electric vehicles leave behind mountains of dead lithium-ion batteries. A new “injection” brings them back to life
BY YOU XIAOYING EDITED BY ANDREA THOMPSON
Illustration, view from above of a couple plugging in an electric vehicle to recharge a low or dead battery, indicated with a battery icon with 2 red bars superimposed on the roof of the car
Batteries
A team of researchers in China has found a way to bring dead lithium-ion batteries back to life, potentially reducing both the amount of waste that’s quickly piling up from spent electric vehicle (EV) batteries and the need to produce as many new ones.
“The team’s work is revolutionary because it provides a new idea to reuse end-of-life batteries,” says Jiangong Zhu of Tongji University in Shanghai, who researches battery use in EVs and was not involved in the new study, which was published recently in Nature.The amount of spent lithium-ion batteries that need disposal is expected to soar from an estimate of 900,000 metric tons this year to 20.5 million metric tons by 2040, according to a report released by the United Nations Development Program last September. As the world’s leader in deploying EVs, China is already handling 2.8 million metric tons of retired cells ever year, according to Huang Jianzhong, chairman of China Electronic Energy Saving Technology Association, a government-approved trade body.
With consumer markets and waste piles both growing rapidly, Yue Gao, a chemist at Fudan University in Shanghai, and his colleagues anticipated a rising demand for longer-life lithium-ion batteries.
An EV battery usually reaches the end of its lifetime, or when its capacity drops below 80 percent of its original level, after about eight to 10 years. The battery accounts for around 40 percent of the cost of the entire vehicle.
Gao and his colleagues wanted to find a molecule that could replenish a dead cell by infusing it with lithium ions. But “we had no idea what kinds of molecules could do that job or what their chemical structures would be, so we used machine learning to help us,” says Chihao Zhao, a Ph.D. student at Fudan University, who is a member of Gao’s team but was not a co-author of the new study.
Experimental setup showing electrolyte being injected into a spent blue battery pack on a white lab bench
Lithium ions were restored to a spent battery pack by injecting an electrolyte solution.Zhao Chihao
The researchers used an artificial intelligence model trained on the rules of chemistry. They fed it a database of electrochemical reactions and had it look for molecules that would meet their requirements, such as dissolving well in an electrolyte solution and being relatively cheap to produce. The model recommended three candidates, and the team identified one of them, a salt called lithium trifluoromethanesulfinate (LiSO2CF3), as ideal.