Researchers at Rice University in Houston say they have a solution to deal with difficult-to-recycle lithium-ion batteries used in electric vehicles, cell-phones and various other electronic devices. Using an environmentally friendly deep eutectic solvent, the solution can extract recyclable elements from the metal oxides commonly used as cathodes in lithium-ion batteries. The researchers say that the goal of the solution is to recycle batteries and also to keep batteries out of landfills.
Materials scientists Pulickel Ajayan and colleges at a Rice laboratory say they have used an environmentally friendly deep eutectic solvent to extract, recyclable elements from the metal oxides commonly used as cathodes in lithium-ion batteries. The solvent, made from choline chloride and ethylene glycol, extracted more than 90 percent of cobalt form powdered compounds, and a smaller but still significant amount from used batteries, according to the researchers.
“Rechargeable battery waste, particularly from lithium-ion batteries, will become an increasingly menacing environmental challenge in the future as the demand for these through their usage in electric vehicles and other gadgets increases dramatically,” says Ajayan. “It is important to recover strategic metals like cobalt that are limited in supply and are critical for the performance of these energy-storage devices. Something to learn from our present situation with plastics is that [now] is the right time to have a comprehensive strategy for recycling the growing volume of battery waste.”
The researchers have built a small prototype battery and found that the prototype could recover rare, in-demand metals such as cobalt, through precipitation and electroplating to a steel mesh, with the latter method potentially allowing for the deep eutectic solvent itself to be reused.
“We focused on cobalt,” says Rice alumnus Marco Rodrigues, now a postdoctoral researcher at Argonne National Laboratory. “From a resource standpoint, it’s the most critical part. The battery in your phone will surely have lots of it. Lithium is very valuable too, but cobalt in particular is not only environmentally scarce, but also, from a social standpoint, hard to get.”