Rechargeable batteries can now be made without rare metals, making them greener. But that very progress makes recycling more difficult – and the waste problem is piling up. Now, a study shows that improving waste management may make recycling profitable.
The recycling of rechargeable batteries is a growing challenge – especially because they are already present in millions of electric cars and are used to store green electricity.
At the heart of the problem is economics: without a viable business model for recycling, green batteries risk piling up in mountains of waste within just a few years – instead of becoming a valuable raw material.
Paradoxically, the problem stems from increased sustainability:
It was a different story in the past, when rechargeable batteries inevitably contained rare metals such as cobalt and nickel. This made the batteries less sustainable, but cobalt and nickel were so valuable that it was worth extracting them from waste – almost like finding gold in the rubbish bin.
Today, many rechargeable batteries contain lithium iron phosphate and graphite. They are less expensive and more environmentally sound – but because they do not contain expensive metals, making a business of recovering them from the waste stream is difficult.
But new research from Aarhus University shows that with the right processing, even today’s dead batteries may be profitably recycled.
“If we do not figure out how to recycle modern rechargeable batteries on a larger scale, we will face a major problem with a lot of useless battery waste. This study shows that battery waste may still be turned into a good business,” explains Dorthe Bomholdt Ravnsbæk, Professor, Department of Chemistry, Aarhus University, Denmark.
The research has been published in Batteries. The results add to an international debate in which both the European Union and the United States are working to develop better methods for recycling batteries.
This is what a broken battery looks like inside
Crushing a battery produces a black powder called black mass. It looks like coffee grounds mixed with metal scraps and acts like a bowl of mixed LEGO bricks: the challenge is to fish out the valuable pieces.
Some items can be sorted out because they are heavier – like shaking a bag of mixed nuts and the largest ones fall to the bottom. Other parts, such as metals, can be pulled out with magnets – like picking up nails from the ground by using a magnet.
But lithium iron phosphate and graphite are not as easy to separate: they cling together as inseparably as coffee and milk once mixed. Until now, this has meant destroying everything and starting from scratch.
Zooming in on battery dust
In the study, Dorthe Bomholdt Ravnsbæk and her colleagues examined black mass from a company that handles battery waste.
The purpose was to determine whether there are opportunities to recycle lithium iron phosphate rather than completely breaking it down.
The researchers divided the battery powder into small portions and discovered that lithium iron phosphate accumulates in specific places – key to enabling recycling.
The researchers made a crucial discovery: graphite easily separates from its metal substrate, whereas lithium iron phosphate remains firmly attached. This difference can be exploited – and could be the breakthrough that transforms battery waste into a real business opportunity.
“This means that you can adjust how the batteries are crushed so that the lithium iron phosphate ends up more concentrated in one place. This may enable a more direct recycling process,” says Dorthe Bomholdt Ravnsbæk.
Better sorting can save more materials
The researchers also point to a pitfall: when battery waste is heated, the lithium iron phosphate is destroyed. It is like baking a cake and then trying to get the ingredients back – impossible, because the material loses its value during heating. In short: heating destroys the material, robbing it of value before it ever reaches recycling so it should not be done if you want to retain the possibility of recycling the material.
The research shows how lithium iron phosphate and graphite behave in battery powder – and how to improve sorting so that lithium iron phosphate can be recycled.
“We definitely see an opportunity to improve how batteries are crushed – and how the powder is processed afterwards,” notes Dorthe Bomholdt Ravnsbæk.
Recycling benefits both nature and the wallet
Dorthe Bomholdt Ravnsbæk explains that creating an industry based on recycling lithium iron phosphate from rechargeable batteries would be a huge gain.
Creating such an industry would not only create a new business but would spare nature mountains of used batteries – and take a step closer to the circular economy, the ultimate goal.
“Lithium iron phosphate does not have the same value as cobalt and nickel, but considerable money can be saved by recycling this material instead of creating it from scratch. This can give battery waste greater value rather than just throwing it away,” says Dorthe Bomholdt Ravnsbæk.
She elaborates that even if the graphite ends up being discarded, it would still be a great step towards circular economy if the lithium iron phosphate could be recycled.
“A dead battery does not mean dead materials. Lithium iron phosphate can live on – which is precisely why used batteries should be seen as raw materials ready to re-enter the cycle,” concludes Dorthe Bomholdt Ravnsbæk.
