Researchers have developed a new method that can efficiently recycle lithium from old electric vehicle batteries. The low-cost electrochemical method, developed by a group of University of Wisconsin-Madison chemists, recycles lithium from used EV batteries.

The team extracted lithium from spent lithium-iron-phosphate (LFP) batteries. 

Researchers demonstrated the process’s viability using a commercial LFP battery and black mass.Image: zhihao/JEFF MILLER. 

Researchers also pointed out that recovering lithium from spent LiFePO4 batteries using conventional methods may not be economically viable because there are no valuable metals to recover in LiFePO4 other than lithium. 

Lithium recovery from spent LFP batteries

“At this point, there’s no economically compelling method to recover lithium from spent LFP batteries even though the market is shifting to them,” says chemistry professor Kyoung-Shin Choi’s, who noted that obtaining lithium from mines and brine deposits has many negative environmental consequences, even if it may be cheaper than recycling.

“Access to these natural lithium resources is also limited,” said Choi. “We need an innovative method that makes lithium recovery from spent LFP batteries commercially viable to support a circular and competitive battery economy.”

Published in ACS Energy Letters, the study reports the invention of an electrochemical system, composed of a Li+-extraction cell and a Li+-recovery cell, which can recycle Li+ from spent LiFePO4-LIBs as Li3PO4, Li2CO3, or LiOH using simple and cost-effective procedures.

“While recovering Li+, these cells also regenerate the acid consumed for Li+ leaching, minimising the chemicals needed and the waste generated, enabling sustainable and environmentally benign Li+ recycling. The choice of electrodes, operation principles, performance, and variation of the Li+-extraction/recovery cells are reported,” said researchers in the study.

Electrochemical process doesn’t require special conditions

Choi’s two-step electrochemical process that doesn’t require special conditions and minimises chemical inputs and waste. The first step sees lithium ions leached out from spent LFP batteries and selectively extracted by a lithium-ion storage electrode. In the second step, the extracted lithium ions are released in a separate solution to recover them as high-purity lithium chemicals, according to a press release.

Choi and her colleagues have demonstrated the process’s viability using both a commercial LFP battery and black mass, which is an industrially mass-produced substance from spent LFP batteries.

“The technology works, but it is important to scale it up in the most cost-effective manner,” said Choi, adding that it will be crucial for successful commercialisation to streamline the technology with other steps in the overall recycling process such as the production and use of black mass.

Lithium-based EV batteries come in a few flavours, and while LFP batteries have lower energy densities than batteries that are based on elements like nickel, manganese, and cobalt, they are significantly cheaper to produce and safer to operate.

On the flip side, iron and phosphate are not worth much compared to nickel or cobalt, making LFP batteries less attractive from a recycling perspective, according to researchers.