Researchers at Worcester Polytechnic Institute have developed a new way of recycling lithium-ion batteries, a breakthrough they say will help reduce battery waste and bolster supplies of metals critical for clean technology.
Compared to traditional recycling methods, the researchers say the new process recovers metals from discarded batteries more efficiently. The metals can be reused in new batteries for electric vehicles, power grid storage and other common electronics.
WPI engineering professor Yan Wang led the research, which was recently published in the peer-reviewed journal, Energy Storage Materials. Wang said the new approach comes as batteries become an increasingly vital source of renewable energy, and yet pose their own environmental challenges as they reach the end of their lifespans.
“Recycling is very important,” Wang said, noting that if batteries are disposed of improperly, “they can catch fire” and leach toxic chemicals.
Similar to traditional recycling, Wang said the new process involves dissolving battery components in an acidic solution to extract metals like nickel, cobalt and manganese. The difference lies in what happens to those metals afterward.
The typical approach separates them, leaving raw materials that can be sold individually. In order for those metals to be reused for a new battery, they need to be combined again, which can be energy-intensive and costly.
The new method developed by the WPI team is more efficient because it keeps the metals together throughout the process. All battery developers have to do is add more nickel or cobalt to the mixture to reach the desired concentration of metals.
“It’s a simpler [process],” said Jiahui Hou, a postdoctoral researcher at WPI who collaborated on the study. “It just skips one step.”
The new recycling process uses 8.6% less energy and releases 13.9% fewer carbon emissions than conventional methods while still recovering 92% of critical metals from used batteries.
Testing showed that batteries created using the new recycling approach performed especially well. The batteries retained 88% capacity after 500 charge cycles and more than 85% after 900 cycles, which is on par with batteries using new, non-recycled materials.
Wang said the breakthrough could be especially beneficial for battery supply chains as global demand for critical metals increases. The United States relies heavily on imported metals for batteries, he noted, leaving it susceptible to other countries’ control of metal exports. The U.S. can reduce that dependence by building up its own supply of metals via recycling.
“We use loads of batteries, and eventually after we’re recycling, we can still keep all the materials in the U.S.,” Wang said. “The potential is huge.”
