Anna-Caroline Lavergne Bril, IMDEA MATERIALS
Your electric vehicle battery reaches the end of its life. What happens next? Inside it, among many other materials, is cobalt, a valuable metal that is considered critical for Europe but remains difficult to recover economically.
In our laboratory, we are investigating ways to give this material a second life. Rather than simply recycling it to manufacture more batteries, we are transforming it.
By combining recovered cobalt with nanostructured materials, we can produce flame-retardant battery separators: the ultra-thin membranes that keep a battery’s internal components electrically isolated. Their role is to withstand high temperatures and help suppress fire if something goes wrong.
The idea is simple: the cobalt from yesterday’s battery could help prevent fires in tomorrow’s. What is currently a difficult waste stream could become a safety technology for the future.
Why cobalt matters
The European Union classifies cobalt as a critical raw material due to concerns over supply security and the concentration of its production and processing in only a few regions. In addition, cobalt extraction and refining consume significant amounts of energy, increasing the environmental footprint of batteries.
As global demand for energy storage continues to grow, recovering and reusing cobalt from end-of-life batteries has become a strategic priority.
However, this is far from straightforward. When a battery reaches the end of its useful life, recovering cobalt requires dismantling complex energy-storage systems and separating it from other valuable metals such as nickel and manganese.
It is estimated that producing 1 kg of cobalt consumes around 250 kg of water and generates at least 100 kg of waste.
Paradoxically, although cobalt is one of the most valuable materials contained in a battery, it is also one of the most difficult to recover economically.
For this reason, researchers are exploring approaches such as upcycling, which involves transforming materials recovered from used batteries into higher-value products with new applications.
Why Recovering Cobalt from Batteries Is So Challenging
The battery of an electric vehicle is a highly complex system that can weigh hundreds of kilograms and contains plastics, aluminium casings, electronic components, modules, and individual cells.
Before any valuable material can be recovered, all these elements must be safely dismantled, a labor-intensive process that involves significant electrical hazards.
Once the cells have been removed, the electrolytes are extracted and easily separable materials such as aluminium and copper are recovered.
The Challenge of Black Mass
What remains is a mixture known as black mass, a fine powder containing valuable metals such as cobalt, nickel, and manganese.
The real challenge arises at this stage. The metals contained within black mass cannot be separated mechanically and must instead be recovered through energy-intensive metallurgical processes.
The most common approaches are pyrometallurgy, which relies on high temperatures, and hydrometallurgy, which uses chemical solutions to separate and recover different metals.
Both methods are technically demanding. In hydrometallurgy, selectively recovering individual metals requires multiple chemical processing stages, and obtaining pure cobalt remains difficult because of its similarity to elements such as nickel.
Separating these metals requires additional processing steps, increasing both costs and energy consumption.
There is also an economic challenge. Even after batteries have been collected, transported, and dismantled, numerous refining stages must still be carried out, many of them similar to those used for processing newly mined ores.
As a result, recycling can be more expensive and resource-intensive than conventional extraction, particularly while the volume of end-of-life batteries remains relatively limited.
Upcycling: When Recycling Is Not Enough
Reusing recovered cobalt in new batteries is recycling. Upcycling, by contrast, aims to transform these materials into products with new or enhanced functions.
In addition to creating higher-value materials, this strategy may make cobalt recovery more economically viable and reduce some of the most costly purification steps.
Preventing Fires from Within the Battery
At IMDEA Materials Institute, through the ATENEA programme funded by the Marie Skłodowska-Curie Actions, we are investigating whether cobalt recovered from end-of-life lithium-ion batteries can be incorporated into flame-retardant materials for battery separators.
The concept is straightforward: cobalt extracted from an old electric vehicle battery could help prevent fires in a new one. To achieve this, we combine recycled cobalt with nanostructured materials to develop a new generation of separators that are more resistant to high temperatures and capable of slowing the spread of fire.
If successful, this strategy would not only recover a valuable critical raw material but also give it a new purpose, transforming today’s battery waste into tomorrow’s safety technologies.
Anna-Caroline Lavergne Bril, Research Associate and MSCA Fellow, IMDEA MATERIALS. This article was originally published in The Conversation. Read the original.