Source: The Conversation (Au and NZ) – By Neeraj Sharma, Scientia Associate Professor of Chemistry and ARC Future Fellow, UNSW Sydney
You might have heard the common claim that electric cars aren’t really green – that their lithium-ion batteries rely on “blood” minerals such as cobalt, mined in terrible conditions.
The critique had some truth to it. But this claim is no longer accurate. Electric vehicle (EV) manufacturers have been shifting away from cobalt because it’s expensive, toxic and ethically fraught.
What’s replacing it? Cheaper lithium-ion battery chemistries based on lithium iron phosphate (LFP), which avoid cobalt entirely. If you remember high-school chemistry, you’ll remember batteries have an anode and a cathode. The anode is nearly always graphite. But the cathode can be made from many different minerals and compounds.
This means battery makers have a great deal of choice over which minerals to include. There’s huge innovation taking place in batteries, as the market grows and diversifies across vehicles and energy storage. Even cheaper chemistries are emerging based around salt (sodium-ion), while high-performance solid state batteries are coming close to reality.
What happened to cobalt?
For years, cobalt has been a mainstay in cathodes due to its useful properties, including how much energy it can help store.
When the first commercial lithium-ion batteries arrived in the 1990s, the chemistry relied on cobalt (lithium cobalt oxide). Over time, lithium nickel mangananese cobalt (NMC) oxide and lithium nickel cobalt aluminium (NCA) oxide came to dominate the market, as their high energy density made them ideally suited for portable electronics.
As demand for lithium-ion batteries accelerated, sourcing cobalt began to be a problem. Three quarters of mined cobalt comes from one country: the Democratic Republic of Congo (DRC), which has half the world’s reserves. Australia is second, with 20%.
Cobalt is toxic. In the DRC, many people risk their health in small mines under conditions often described as slave-like. Illegal and legal mines can do huge environmental damage.
This and other issues led researchers to begin working on reducing or cutting cobalt out altogether. This led to low-cobalt chemistries, in which most of the cobalt was swapped for nickel, manganese or aluminium. To date, it’s been difficult to remove cobalt entirely, given how much of a boost it gives to battery capacity and stability.
In parallel, US researchers found the mineral olivine – made of lithium, iron and phosphate (LFP) – was a good candidate for battery cathodes. This discovery gave rise to cobalt-free LFP batteries. LFP chemistry is cheap, non-toxic and safe, though slightly less energy-dense.
These batteries have had a meteoric rise. Last year, 50% of all EV batteries and more than 90% of stationary home and grid batteries used this chemistry.
Given world-leading battery makers now rely heavily on this chemistry, it’s likely LFP batteries will dominate the market for EV and stationary storage applications in the near term.
What’s on the horizon?
The global market for lithium-ion batteries has risen sixfold since 2020 and strong growth is projected to continue. EVs are taking more and more market share – especially in developing nations – and huge grid-scale batteries are proving essential in modern power grids.
What’s next?
Many next-generation batteries nearing the market are being developed for specific jobs – such as powering drones – or to outcompete current technology. Here are four new types to watch:
Sodium-ion: The world’s biggest battery maker, CATL, and other manufacturers are exploring an entirely different chemistry – sodium-ion – in a bid to eventually replace lithium-ion batteries as home or grid batteries. Sodium-ion batteries are typically heavier and less energy-dense than lithium-ion, so they wouldn’t work well in vehicles. But the chemistry has real promise for stationary energy storage.
Lithium-sulfur: These batteries rely on lithium and sulfur or sulfur-carbon composites. They can currently store four to five times more energy than traditional lithium-ion batteries, making them particularly useful for drones and other technologies where maximum power is needed. The challenge is giving them longevity, as the reactions in these batteries are harder to reverse. That means these batteries are harder to recharge many times at present. Several Australian companies are active in this space.
Solid state: Until now, lithium-ion batteries have relied on a liquid electrolyte as the medium for ions to shuttle between anode and cathode. Solid state batteries do away with the liquid, making them inherently safer. They could potentially lead to a drastic boost to energy storage. They’re not mainstream yet because it’s still tricky to get them to work at room temperature without using high pressure. If engineers figure this out, an EV using solid state batteries might travel 1,000km on a single charge.
Flow batteries: In the 1980s, Australian engineers at UNSW invented the vanadium redox flow battery. A cross between a conventional battery and a fuel cell, these typically larger batteries can feed power back to the grid for 12 hours or more, much longer than current lithium-ion battery systems.
These batteries are likely to be useful in renewable-heavy power grids. Lithium and sodium-ion batteries could provide shorter bursts of power to the grid, while flow batteries could kick in for longer periods.
So do we still need cobalt?
These developments are promising. But they don’t mean an end to cobalt entirely. Smaller amounts of cobalt will still be in the lithium-ion batteries in portable devices and EVs for the foreseeable future.
What we are likely to see is more recycled cobalt coming into the mix, as governments accelerate recycling of lithium-ion batteries and promote recycled minerals to be used in new batteries. Over time, the role of “blood cobalt” could disappear.
– ref. ‘Blood cobalt’ is disappearing from batteries – and cheaper, cleaner batteries are arriving – https://theconversation.com/blood-cobalt-is-disappearing-from-batteries-and-cheaper-cleaner-batteries-are-arriving-263808
