The scientists started by using a solvent recipe from “green” chemistry that uses deep eutectic solvents (DES), environmentally friendly liquids that precipitate lithium and other metals from solutions.

Salma Alhashim, one of the lead authors of the study, explained that the traditional extraction rate is very low because lithium is usually the last metal to precipitate after all other metals. The team of scientists aimed to focus on lithium specifically.

The researchers used a DES mixture of choline chloride and ethylene glycol, which effectively surrounds lithium ions with chloride ions during the leaching process, facilitating their extraction.

Microwave technology

A major breakthrough occurred with the use of microwave radiation. The improved absorption of microwave radiation by choline chloride acted as a catalyst, significantly accelerating the extraction process.

Sohini Bhattacharya, the study’s other lead author, likened the method to heating food in a microwave oven.

Using microwave radiation for this process is similar to how a kitchen microwave oven quickly reheats food. The transfer of energy directly to the molecules allows the reaction to occur much faster than with traditional heating methods,
– said.

This innovative approach allowed the researchers to extract lithium almost 100 times faster than traditional methods. They achieved 87% lithium extraction in just 15 minutes, a process that would normally take 12 hours using an oil bath.

The flexibility of DES solvent chemistry means they can be adapted to remove other elements, such as cobalt or nickel, from solutions. This clean and fast process could revolutionise future lithium battery supply and recycling chains.