The study, published in Joule, highlights a growing environmental threat from these increasingly popular vape pens, which are not designed to be recharged.
Disposable e-cigarettes have skyrocketed in popularity in the UK since 2021, with a survey finding an 18-fold increase recorded between January 2021 and April 2022. Within 15 months, their popularity among 18-year-olds rose from 0.4% to 54.8%.
This has led to new waste problems, with about 1.3 million of the devices thrown away in the nation each week. As a result, about 10,000 kilograms of lithium from e-cigarette batteries wind up in UK landfills each year, threatening nearby waterways with toxic nickel, cobalt, and organic solvents.
The research team had a hunch that the batteries used in disposable e-cigarettes were rechargeable, but were not aware of any previous studies that had assessed how long the lithium-ion batteries in these products are capable of lasting.
Hamish Reid, first author of the study from UCL Chemical Engineering, said: “Popularity in single-use vapes has exploded recently. Despite being sold as disposable, our research has shown that the lithium-ion batteries stored within them are capable of being charged and discharged over 450 times. This work highlights the huge waste of limited resources caused by disposable vapes.”
To test their hunch, researchers at UCL and the University of Oxford harvested batteries from disposable e-cigarettes under controlled conditions, then assessed them using the same tools and techniques used to study batteries in electric vehicles and other devices.
They examined the batteries under microscopes and used X-ray tomography to map their internal structure and understand the constituent materials. By repeatedly charging and discharging the batteries, they determined how well the batteries maintained their electrochemical performance over time, finding that they could be recharged many hundreds of times in some cases.
Professor Paul Shearing, senior author of the paper from UCL Chemical Engineering and the University of Oxford, said: “The surprise for us were the results that pointed toward just how long these batteries could potentially cycle. If you use a low charge and discharge rate, you can see that for over 700 cycles, you still have more than 90% capacity retention. That’s a pretty good battery, actually. And these are just being discarded. They’re being chucked on the side of the road.
“As a bare minimum, the public needs to be aware of the types of batteries going into these devices and the need to properly dispose of them. Manufacturers should provide the ecosystem for reuse and recycling of e-cigarette batteries, and also should be moving towards rechargeable devices as the default.”
Professor Shearing and his team are also researching new, more selective ways to recycle batteries that allow individual components to be recovered without cross-contamination, as well as more sustainable battery chemistries, including post-lithium ion, lithium sulfur, and sodium ion batteries.
To address challenges across the entire battery supply chain, scientists should consider batteries’ life cycles when thinking about any of their applications.
“That permeates all the work we do, really, whether it’s a vape battery or whether it’s a battery going into an electric helicopter,” said Professor Shearing. “It’s the same kind of thought process where we need to fully understand the life cycle of a battery device.”
This work was supported by the EPSRC CASE Award; the Faraday Institution; the Department of Science, Innovation and Technology (DSIT); and the Royal Academy of Engineering for the Chair in Emerging Technologies; and the National Physical Laboratory (NPL).