Electric vehicles will play a crucial role in humanity’s fossil fuel-free future, but no technology comes without cost. The lithium-ion batteries that EVs run on are made from metals that are mined at a serious environmental and human toll, and from supplies that won’t last forever. When those batteries die, they’re liable to join the tens of millions of tons of spent electronics piling up as e-waste in landfills around the world.
That’s why we badly need to develop better methods for recycling EV batteries and start scaling up the recycling infrastructure now, a team led by researchers at the University of Birmingham in the UK argue in a review paper published today in Nature.
As the paper notes, the one million EVs sold around the world in 2017 will eventually result in 250,000 tons of battery pack waste that the world’s recycling infrastructure is ill-equipped to handle. And while EV batteries can last for up to 20 years, the potential battery waste in the pipeline as EV sales grow year over year is enormous.
“It is important that we anticipate problems before they happen,” said lead study author Gavin Harper, a research fellow at the University of Birmingham’s Faraday Institution. “We have seen in the past with car tires and fridges how waste mountains can arise if we don’t anticipate waste management problems.”
In their paper, Harper and his colleagues try to sketch out what an effective waste management infrastructure could look like for EV batteries, which, in addition to lithium, contain critical metals like manganese, copper, and cobalt. As with consumer electronics, managing waste starts with extending the life of EV batteries as much as possible. When they’re no longer useful for driving, they can be repurposed for other types of energy storage like home batteries—an idea that companies are already pilot-testing around the world.
But eventually, EV batteries will reach the end of their useful life, at which point they need to be recycled. Today, Harper said, most recycling revolves around using heat to melt the batteries down to slag, followed by chemical separation techniques that recover specific metals like cobalt. But these so-called pyro and hydro-metallurgical techniques are energy intensive and produce toxic gas byproducts, and the materials they recover are often low quality.
A better route forward, the authors say, would be direct recycling, where cathodes are rehabilitated for use in new batteries without separating them back to the individual metals. It’s also possible that we could harness so-called biomining microbes that produce acids to liberate key metals from rock—an idea that scientists are also hoping to apply to asteroid mining.
There are flavors of all these techniques in development at universities, startups, and even established companies like Tesla, which this year announced that it would be developing a battery recycling system at its Gigafactory 1. But there are also major hurdles to scaling up, including the cost and complexity of the recycling and the many hazards of dealing with EV batteries, which run at high voltages and can electrocute the person doing the disassembly. These batteries can also overheat and release toxic gases or—much like their counterparts in smartphones—explode.
There’s also no industry-wide standardization in terms of EV battery design. With the configuration and chemical makeup of batteries constantly evolving, any recycling technologies we develop today need to be adaptable—part of the reason Faraday Institution researchers are working to develop artificial intelligence systems that can identify and sort batteries of all shapes and sizes.
Corporations also have a responsibility to design batteries that can be easily taken apart for resource recovery, said Payal Sampat, the mining program director at the nonprofit environmental organization Earthworks.
“Companies must assume responsibility for the end-of-life of their products—which in turn means that products will be better designed for recovering minerals,” Sampat wrote in an email.
While the challenges are significant, the rewards of figuring out how to do this are potentially huge. As a report commissioned earlier this year by Earthworks noted, easily-accessible supplies of battery metals are being depleted rapidly. Annual demand for lithium is projected to surpass current production rates from mines as soon as 2022, and by 2050, demand for cobalt could exceed known planetary reserves.
At that point, the millions of tons of metals locked away in dead EVs are going to start looking pretty appealing.