Scientists develop game-changing new method to recover a key material from spent batteries: 'A promising step'

Microwave science related to the process that heats our TV dinners is now part of a Rice University plan to recover valuable lithium from old batteries, according to a lab report detailing the fascinating findings. 

The experts say they can harvest an unprecedented 50% of the crucial material in 30 seconds. 

It's one of the latest efforts to find a cost-effective, efficient, and planet-friendly way to recycle the metal, an expensive and hard-to-gather power-pack component with a market value of around $65 billion globally, according to Fortune Business Insights. 

Lithium-ion batteries provide energy storage for many of the devices and electric vehicles we use each day. The Rice experts said the market is expected to grow 23% during the next eight years, further straining the metal's supply chain. 

"We've seen a colossal growth in [lithium-ion battery] use in recent years, which inevitably raises concerns as to the availability of critical metals like lithium, cobalt, and nickel," Sohini Bhattacharyya, a lead author on the study, said in the press release. 

The Rice method uses microwave radiation and a specific blend of solvents that work together to extract lithium from battery waste. The report states that common recycling techniques use "harsh acids" that gather less than 5% of the key metal. In turn, multiple reports note that only 5% of lithium batteries are recycled in the U.S. and globally. 

The U.S. government is pumping $62 million into efforts to boost recycling stateside. Large battery makers like China's Contemporary Amperex Technology Co., Limited (CATL) are expanding recycling programs, too. 

The Rice approach uses a mixture of choline chloride and ethylene glycol. The battery junk is submerged in the solution and blasted with microwaves. 

"This allowed us to leach lithium selectively over other metals," Bhattacharyya said in the summary. "Using microwave radiation for this process is akin to how a kitchen microwave heats food quickly. The energy is transferred directly to the molecules, making the reaction occur much faster than conventional heating methods."

Microwave performance far exceeded the traditional hot oil baths used to heat other processes. In fact, the Rice approach could leach 87% of the lithium in 15 minutes. The same yield takes 12 hours with bath heating, per the summary.  

"Another advantage is solvent stability: Because the oil bath method takes so much longer, the solvent begins to decompose, whereas this does not happen with the short heating cycles of a microwave," Salma Alhashim, the study's other lead author, said. 

Recycling can also help to lower the cost of electric vehicles, as noted by the U.S. government. A record 1.2 million EVs were sold in the country last year. Each one that replaces a gas guzzler prevents thousands of pounds of heat-trapping air pollution from exiting exhausts each year on average. Up to $7,500 in tax breaks make the cleaner rides more affordable. Further savings of around $1,500 annually on gas and certain maintenance costs can extend the value throughout the vehicle's life span. 

The World Health Organization reports that e-waste is the fastest-growing solid-waste garbage stream on the planet. Human exposure, sometimes through recycling efforts that create other types of pollution, can be a detriment to human health, particularly for women and children. 

At Rice, the experts think their findings can improve the environmental impact and economics of battery recycling.

This method "makes it a promising step toward deploying … recycling systems at scale," the study's corresponding author, Pulickel Ajayan, said in the summary.

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