It’s a criticism that can be levelled at almost any product that’s ever been manufactured: why are goods never designed in a way that makes them easy to recycle? Be it plastic bottles with unrecyclable labels pasted firmly on, or mobile phones so intricately welded together that removing the valuable metals within is prohibitively expensive – time and again it seems we walk blindly into a waste problem, inventing must-have new products only to find them stacking up in landfill years later or burned to ash.
The key to avoiding these problems is to tackle them before the product in question gets too popular. This is what some scientists are now trying to do when it comes to electric vehicles, or more specifically, the lithium-ion batteries that power them.
As things currently stand, some lithium-ion batteries (LIBs) can be re-used and recycled, but given the growth trajectory of the electric vehicle market, we are nowhere near equipped to deal with the coming onslaught. According to a new study by scientists at the University of Birmingham, sales of electric vehicles exceeded one million cars per year worldwide for the first time in 2017. They calculate that even employing the conservative assumption that an average battery pack weighs 250kg and has a volume of half a cubic metre, the resultant waste would comprise around 250,000 tonnes and half a million cubic metres of unprocessed waste when these vehicles reach the end of their lives.
Failing to recycle these batteries would add hugely to our current waste problem and comes with a range of safety concerns. The Birmingham researchers point to the fire risk of storing large concentrations of battery waste, comparing it to the stockpiles of other materials which have caused problems in the past. Tyres are a good example. For 15 years, from 1989 to 2004, a tyre fire smouldered in Powys, Wales – and the researchers note that the materials in lithium batteries are far more reactive than tyre rubber. They also add that the number of fires being reported in metal-recovery facilities is already increasing, owing to the illicit or accidental concealment of LIBs in the guise of normal lead-acid batteries.
In addition, failing to recycle batteries would mean losing a host of extremely valuable resources held within them, including lithium, cobalt, manganese and nickel. With deposits of some of these resources already scarce, and with ethical and environmental concerns related to their mining and production processes, it would seem wise not to lose these materials.
Professor Andrew Abbott, of the University of Leicester and co-author of the paper, said: ‘Electrification of just two per cent of the current global car fleet would represent a line of cars that could stretch around the circumference of the Earth – some 140 million vehicles. Landfill is clearly not an option for this amount of waste. Finding ways to recycle EV batteries will not only avoid a huge burden on landfill, it will also help us secure the supply of critical materials, such as cobalt and lithium, that surely hold the key to a sustainable automotive industry.’
However, separating these metals from each other isn’t easy. Individual lithium-ion cells are formed into modules, which are then assembled into battery packs. To recycle these efficiently, they must be disassembled and the resulting waste streams separated. ‘If we could think about a circular economy for electric vehicles, we need more sophisticated techniques, that allow us to segregate and separate materials before they enter into the recycling process,’ says Dr Gavin Harper, Faraday Research Fellow at the University of Birmingham and lead author on the paper.
Harper explains that in the UK, lithium batteries are usually sent to Belgium, where they are treated to a pyrometalurgical process – which essentially involves putting them into a furnace. ‘The challenge with that is that you actually lose quite a significant portion of the material,’ says Harper. ‘It’s very good at extracting the cobalt and the nickel, which are of high value and which we are concerned about. But the lithium, aluminium and manganese end up in a slag from which it is very difficult, expensive, energy intensive and uneconomical to recover them in a form that is useful for batteries again.’ As a result, he and his fellow researchers point to the need to sustain and increase investment and research into new both new recycling techniques and new battery design.
On the plus side, Harper says there is already a huge amount of research being done in both of these areas. The research paper points to two recycling techniques called hydrometalurgy and direct recycling, which have the potential to allow for greater recovery of material, though each comes with its own set of technical challenges.
Hydrometallurgical treatment involves the use of aqueous solutions such as water to leach the desired metals from the surrounding cathode material. Direct recycling involves keeping the material in much the same form and cleaning it, rejuvenating it and putting it into a new battery. In principle, all battery components can be recovered and re-used after further processing.
In addition, Harper adds that scientists around the world are also working to create more efficient batteries – in particular, batteries with a much lower cobalt content. At least 50 per cent of cobalt is currently sourced from the Democratic Republic of Congo, but in addition to well-documented human rights abuses in the region, researchers claim that output from mines is already falling below demand.
Harper’s own team is also working on a new paper which will analyse the potential to redesign lithium batteries in a way that would make them easier to separate at the end of their lives. ‘We believe that there are things that could be done in terms of the intelligent design of batteries to make them much more easily sustainable,’ he says. ‘For example, with robotic disassemblies, having flexible cables in a battery pack is difficult – it’s like spaghetti and weaves around everything. If you could replace that with a solid interconnect, you'd have something that was much more predictable and easier to remove. There are lots of clever approaches like this. Combined with smart recovery, they can enable us to separate materials in the battery before recycling. This really is the key.’
In fact, far from being a harbinger of doom, Harper is keen to point out that all of this could present a huge opportunity for the UK. Analysis by the Faraday Institution – the UK’s independent institute for electrochemical energy storage research – points to the need for eight gigafactories in the UK by 2040 to mass produce batteries and service the demand for electric vehicles. The UK will need to develop sources of supply for the materials required for these batteries and recycled material could play an important role.
‘It’s all right having the factories, but those factories require materials to keep them going,’ points out Harper. ‘We need to think carefully about where those materials are going to come from.’ He notes that due to various geopolitical forces – including the fact that China is currently buying up many of the largest mines – a ready supply is not necessarily guaranteed. ‘Some will have to come from foreign resources,’ he accepts, ‘but there’s also an opportunity to develop a fantastic industry in the UK around reclamation, recycling and recovery. I think there’s a concerted global push around battery recycling. There is a lot of investment both by government and industry, and the recognition that this is a problem. I don’t think this is something that is going to catch us completely unawares.’
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