A team of researchers at Rice University has developed a new method that retrieves up to 50% of lithium from spent lithium-ion battery (LIB) cathodes in just 30 seconds.
The innovative approach utilizes microwave radiation and a biodegradable solvent, providing a more efficient and environmentally friendly method for selective lithium recovery, according to the study.
Current recycling techniques often rely on harsh acids, while eco-friendly alternatives like deep eutectic solvents (DESs) have struggled with efficiency and economic feasibility, typically recovering less than 5% of lithium due to contamination and energy-intensive processes.
“The recovery rate is low because lithium is usually precipitated last after other metals,” explained Salma Alhashim, a lead author and Rice doctoral alumna.
“Our goal was to specifically target lithium using a DES mixture of choline chloride and ethylene glycol, which surrounds lithium with chloride ions and leaches it into the solution,” she said.
The team found that choline chloride, a component of the DES, effectively absorbs ‘microwaves’. By submerging battery waste in the solvent and applying microwave radiation, they could selectively leach lithium over other metals.
“This process is similar to how a kitchen microwave heats food quickly,” said Sohini Bhattacharyya, one of the two lead authors on the study.
“The energy transfers directly to the molecules, accelerating the reaction far beyond conventional heating methods.”
Compared to oil bath heating, which requires 12 hours to recover 87% of lithium, the microwave-based process achieves the same recovery in just 15 minutes.
Valued at over $65 billion in 2023, the lithium-ion battery global market is expected to grow by over 23% in the next eight years.
