Driving sustainability in the unfashionable side of battery production: Stora Enso writes for ICON

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Lauri Lehtonen (Image: Stora Enso)

With increasing demands for electrification and rising standards of living, it’s essential that we find new and smarter technologies to meet the future, Lauri Lehtonen from Stora Enso tells ICON in his thought piece.

 

 

Batteries are big business – and a big conversation point, too. By now, most reasonably informed people will be aware that batteries are an essential tool in the fight against climate change thanks to their use in electric vehicles, and other technologies.

With that awareness has come a justified concern for just where to sustainably source all the materials for these batteries.

Commonly, this concern leads to discussions about where to source the likes of cobalt, lithium and – more recently – nickel.

Those are vital conversations to have – but not the only ones we should be having.

All of these oft-discussed materials go into the chemistry for a lithium-ion battery’s cathode. If you remember your high school science, that leaves a large part of the battery unaccounted for: the anode.

The anode has been a less fashionable discussion point; however, it has its own set of sustainability issues.

The key element here is graphite, which can be mined but is more often refined from fossil fuels using carbon intensive processes. Crucially, around “96% of all anodes in lithium-ion batteries contain natural and/or synthetic graphite as their primary material with each requiring 10-15 times more graphite than lithium”.

Let us be clear – this does not mean that batteries are therefore unsustainable and cannot be part of the solution to climate change. Let’s not throw the baby out with the bathwater.

But wouldn’t it be better if there was a cleaner, renewable alternative for this under-discussed part of battery chemistry? And wouldn’t it be better still if (for supply security and sustainability reasons) that alternative could be sourced right here in Europe?  Fortunately, there is just such an alternative.

 

The problem with graphite

What is exactly so bad about today’s graphite supply? Broadly speaking, there are two ways to supply graphite.

One is to mine it. These mines – often open-pit mines – have been shown to produce harmful dust emissions, and purification involved large quantities of chemicals that are hazardous to both the environment and human health.

The alternative is synthetic production. This is a multi-stage process with associated emissions at each step of the way. First, graphite coke is produced from crude oil at oil refineries. Not many refineries are equipped to produce this specialist substance – in fact only one in Europe can do so: the Humber Refinery in the UK. This is an energy intensive process and it is applied to fossil fuels.

Next, the graphite coke is typically shipped somewhere with cheaper energy costs for onward processing. The shipping itself incurs emissions, and the next stage does too. Here, it is cooked at high temperatures (often using coal-fired power) to create a powder that is then applied to copper sheets to form the battery anode.

At each stage, there are clear environmental issues with this process. However, there has historically been little choice if we are to meet surging global battery demand: according to environmental consultancy Minviro, “around 75,000 tonnes of graphite is required to create 1 million EVs, meaning that 900,000 tonnes will be required to meet the 12 million EVs that will be produced by 2025”.

 

 

A homegrown alternative

Enter a material called renewable hard carbon. Not only can renewable hard carbon replace graphite in the anode (fully or partially, as a mix), but it offers significant performance benefits thanks to structural differences with traditional graphite.

These include faster charging and discharging, higher cycling stability and better performance at low temperatures – critical especially for electric vehicle drivers in Northern Europe, who can suffer reduced range in winter with today’s batteries.

Hard carbon is not in itself new. The most exciting thing about renewable hard carbon is that first word: renewable.

Renewable hard carbon is produced using a material called lignin, which makes up about 20-30% of a tree, where it acts as a binder and gives wood its stiffness and resistance to rotting. Lignin is already produced in abundance as a by-product by the European forestry industry, and is typically used today as a biofuel.

Instead, new processes can use the lignin to create renewable hard carbon – and it doesn’t even require more trees to be cut down, it only means that more value is derived from each tree.

With the high forestry standards and sustainable practices of Europe, the material is completely renewable, and comes from 100 per cent traceable and certified resources. It is produced in Europe, and can be used by Europe’s growing battery manufacturing sector, removing the need for materials to criss-cross the globe as is common with synthetic graphite.

Of course, renewable hard carbon is a new material to the battery market, and it will not replace graphite overnight. The material is the result of more than seven years research and development by Stora Enso and is marketed under the name Lignode. The raw material is already in place, and the next steps are to scale up production and collaborate with battery OEMs to commercialise new battery products using the material.

However, though there is still work to do, all signs point to a homegrown European renewable alternative to mined or synthetic graphite, ready and waiting to turbocharge European battery production and move the needle on sustainability.

 

 

Lauri Lehtonen is Acting Head of the new Lignode business for Stora Enso, a paper and forest product manufacturing company headquartered in Helsinki, Finland. His aspiration is to create a better future for the generations to come, by developing new opportunities to replace fossil-based materials.