Circular Economy

Lemon improves recovery of critical raw materials from lithium batteries

Discovery of a sustainable method for the recovery of critical raw materials from end-of-life accumulators

With the mountain of lithium batteries at the end of life constantly increasing, solutions for recycling and recovery of materials are increasingly urgent. The conventional process, however, recovers few materials and uses hazardous chemicals. Researchers at the Oak Ridge National Laboratory of the US Department of Energy looked for an alternative. So, they came up with a method that improves the recovery of critical raw materials from batteries.

It’s all about dissolving the accumulator in a liquid solution to reduce the amount of hazardous chemicals used in the process. Researchers talk about it as a simple, efficient and environmentally friendly solution.

The spent battery is immersed in a solution of organic citric acid (the one found in citrus) and ethylene glycol. The latter is an antifreeze agent commonly used in paints and cosmetics. Citric acid, for its part, is much safer to handle than inorganic acids. The solution allows a surprisingly efficient cathode metal separation and recovery process.

The latter is the most expensive part of batteries, accounting for 30% of total costs. With the technique developed by American researchers, it was possible to eliminate almost 100% of cobalt and lithium from the cathode without introducing impurities. In addition, 96% of the cobalt was recovered in a few hours, without the typical addition of additional chemicals.

In practice, scientists found for the first time a way to perform both leaching and recovery functions at the same time. Not even the researchers, in fact, expected a cobalt precipitation in a purity that could be easily recovered.

Ultimately, the process is faster, cleaner and more efficient than those currently used. The Oak Ridge National Lab team is therefore confident that it will find its way to commercialization.

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