Closing the loop on battery manufacture
One of the major impacts of electrification of cars is the increased demand for lithium-ion batteries. But one of the major impacts of increased demand for lithium-ion batteries is increased waste. A team of polymer scientists at WMG, University of Warwick, is working on a way of making batteries more recyclable, with the aim of closing the loop on battery manufacture.
Recycling rates of lithium-ion (LI) batteries – the type we most commonly use in electric vehicles – are very low in comparison to other battery types.
“Only five per cent of LI batteries are recycled in the EU,” explains Dr Jean Marshall, a polymer chemist by training, who is working in Dr Vaneessa Goodship’s research group on ways to extract and reuse the plastic portion of battery cells.
“It’s to do with process but also to do with the lack of infrastructure. As electric car use increases, so too will the pressure to find better ways of recycling and reusing LI batteries.
“The current process involves shredding the whole thing and trying to recover the valuable bits - like cobalt, which is a precious resource as it is limited in the earth’s crust. The easiest way to do this is to burn everything off until you are left with the metal – or you can precipitate the metals out. But both these processes still waste a lot of the battery cell and produce a lot of tricky bi-products. We are trying ways of doing things more efficiently.”
One of the major ways the whole process can be improved is by looking at recovering the plastic part of the battery cells.
Dr Marshall explains: “We are all aware of the impact of plastics on the planet and we know there are better ways of using or reusing what is a very practical material. We just need to do it better.”
The WMG polymer team looked at solvent extraction of the plastic parts of LI batteries.
“Solvents are not the most environmentally friendly option in many cases but we looked at the most benign options available. This was a challenge because fluoropolymers used in battery cells are very chemically inert which means they don’t react much and they don’t dissolve in many substances. So we set out to find the most sustainable option of those which would do the job.
“The full life cycle analysis of the new method of battery recycling is still ongoing – this will tell us whether we are reducing the impact of LI by using this recycling method. But what we have done using this process is produce quite pure materials and recover enough for the wider project team touse in the manufacture of new batteries. So, we have proved that this is a possible technique for the future.”
As a polymer chemist working in a research role collaborating closely with industry Dr Marshall’s work covers a number of areas where plastics are used. One of the key fields of research at the moment is developing sustainable coatings.
She explains: “Motor vehicles are full of components made of recyclable materials but then coated with something non-recyclable. Most recyclable things can be melted and this is how we reclaim and reuse the materials. But in automotive components or batteries, of course, things need to withstand high temperatures and cannot be allowed to melt – that is why we coat them in something to make them hard and heat resistant. However it means when the component fails the whole thing becomes waste – and this is not sustainable. Our challenge now is to find novel materials which are durable and also recyclable.”
Having worked both in industry and academia, the mission to apply research to real world situations and find better, more sustainable solutions continues to drive Dr Marshall. However the plastics challenge is much bigger than science.
She says: “Plastic is a fantastic material which has brilliant properties but we do need to find solutions to make it reusable and recyclable. For plastic to be truly circular, answers do need to come from chemistry and engineering, but there is also a massive challenge within infrastructure and also psychology. It is no use chemists inventing something that is biodegradable without society adopting it. People need to be on board too – but I think we are definitely making strides in both directions.”
11 February 2022
Dr Jean Marshall is a polymer chemist. She is a research fellow working at WMG, University of Warwick.
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