How an acid found in grapes could help recycle battery metals - Energy & Green Tech - Hi Tech & Innovation

Evaluation of batch-scale selective Co electrowinning from NMC111 leachate. Credit: Science Advances (2026). DOI: 10.1126/sciadv.aec7956

Cobalt and nickel are vital components for batteries, superalloys and catalysts, used in technologies ranging from smartphones to jet engines. But when it comes to recycling, they are notoriously difficult to separate because they are chemically nearly identical. To solve this, a team led by scientists at Johns Hopkins University in the United States has developed a cleaner and cheaper way to extract these elements. And it is thanks in part to grapes.

Demand for both cobalt and nickel is increasing, which puts the world at risk of shortages and price hikes. While recycling is an obvious answer to ensure there is enough to go around, current methods are expensive, rely on harsh chemicals and involve multiple complex stages.

Electrowinning gets a bioacid boost

This new approach is based on electrowinning, which uses electricity to extract metals from a liquid solution and plate them onto a surface, similar to how jewelry is plated with gold and silver. However, there is a problem with cobalt and nickel. They tend to plate at the same time because they react similarly to the electrical current.

The scientists thought they could use a bioacid to help separate them because they are known to bind metal ions differently. The team just needed to find the most suitable one. To do this, they screened 13 different candidates as they detailed in a paper published in Science Advances.

Grape-derived acid delivers the edge

The scientists tested a variety of bio-derived organic acids to see which one could best distinguish between the two metals. They discovered that tartaric acid, found in grapes, was the most effective at binding to nickel ions and separating them from cobalt.

To confirm their findings, they ran computer simulations to see how the molecules interacted at the atomic level. The models showed that tartaric acid binds more strongly to nickel ions, keeping them in the solution, while cobalt can be recovered first.

Promising recovery rates and next steps

When they first tested the process in a small batch, the researchers extracted 99.1% of cobalt. Then, in a larger continuous flow system, they recovered 95.1% of the cobalt and 96.5% of the nickel.

"By providing a scalable, cost-effective, and sustainable alternative, this work establishes a universal strategy for the separation of critical transition metals, addressing a key bottleneck in resource recovery and circular economy efforts," wrote the study authors in their paper.

The researchers are now testing their process on real battery waste and suggest the approach could be adapted to separate other critical metals. 

by Paul Arnold, Phys.org

edited by Gaby Clark, reviewed by Robert Egan 

Source: How an acid found in grapes could help recycle battery metals