Lithium-ion batteries are at the heart of the energy transition, powering everything from cell phones to electric vehicles. But rising demand for lithium could soon outstrip supply, exacerbated by carbon neutrality goals and geopolitical tensions. Currently, lithium recycling is both inefficient and environmentally damaging, with traditional methods recovering little more than 5% of the metal.

Researchers at Rice University led by Pulickel Ajayan have developed a groundbreaking method for extracting lithium from battery waste using microwaves and a biodegradable solvent. The technique can recover up to 50% of the lithium in just 30 seconds, a significant improvement over conventional methods. Advanced functional materialsthe scientific journal that published this study highlights that this innovation could revolutionize lithium-ion battery recycling. Conventional recycling methods often rely on aggressive acids or environmentally friendly solvents such as deep eutectic solvents (DES), which have proven to be costly and inefficient. These processes are also very energy-intensive and rarely recover more than 5% of the lithium due to losses and impurities. To overcome these challenges, the Rice team opted for a DES made of choline chloride and ethylene glycol, which can encapsulate lithium ions and extract them in solution.

Salma Alhashim, one of the study’s lead authors, explains that choline chloride, one of the components of DES, efficiently absorbs microwaves, allowing the mixture to heat up quickly. By immersing battery waste in this solvent and exposing it to microwaves, the researchers were able to successfully extract lithium selectively and separate it from other metals such as cobalt or nickel.

The use of microwaves for this process is similar to that of a domestic microwave oven, where the energy is transferred directly to the molecules, speeding up the reaction. This method achieves similar recovery rates to conventional methods, but in just 15 minutes compared to 12 hours with an oil bath.

One of the main advantages of this approach is the stability of the solvent. In an oil bath, which requires a longer processing time, the solvent actually begins to decompose, whereas this problem is avoided thanks to the short heating cycles provided by microwaves. This advance could significantly improve the economic and environmental impact of lithium-ion battery recycling and provide a sustainable solution to a growing global problem.