By Irina Slav
With the rush of newly minted investors into the EV space, news about electric vehicle technology now rivals that of climate change. Most of the news is good and the latest in batteries is no exception: researchers have managed to make a lithium metal battery last for 600 cycles.
Here’s some clarification upfront: lithium-ion batteries are made up of a lithium-containing cathode and an anode, usually made from graphite. They also feature an electrolyte solution through which lithium ions shuffle back and forth as the battery charges and discharges.
Lithium metal batteries, on the other hand, have an anode that is made from lithium rather than graphite. Lithium is much lighter than graphite and reduces the total weight of the battery. This lighter weight also helps the battery store a lot more energy.
What’s more, lithium metal batteries are a newer technology, which means there’s more space for innovation, while lithium-ion technology is “rapidly approaching their theoretical limit on energy density,” as one scientist from the SLAC National Accelerator Laboratory put it last year.
Unfortunately, as is the case with any technology, not all the news is good. The replacement of graphite with lithium in the anode makes the usual electrolytes used in lithium-ion batteries unusable so new electrolytes need to be developed. This has proved challenging, so for all its advantages, lithium-ion technology has yet to get out of the lab and before it does that, it needs to prove it can make batteries with lithium anodes last at least as long as the lithium-ion ones.
The problem with lithium metal batteries is their short life, so this is what scientists have been focusing on lately. Last year, a SLAC National Accelerator Laboratory team reported it had succeeded in making a lithium metal battery last for 420 cycles of charging and discharging. That’s up from an average of 30 cycles for previous lithium metal batteries, so it’s quite an advancement. To compare, the average lithium-ion battery for EVs lasts for a few thousand cycles.
Now, another team of scientists, from the U.S. Department of Energy’s Pacific Northwest National Laboratory, has announced a battery that can last for up to 600 cycles, and even once this number was reached, it still retained close to 80 percent of its capacity.
This is a promising step in the direction of longer-lasting, more energy-dense EV batteries that could help make EVs the dominant way of passenger transportation. And these steps are being made quickly: scientists working on lithium metal batteries have gone from 50 to 600 cycles in the span of just four years. As for how soon these batteries will leave the lab to enter actual EVs, it remains to be seen but it may be soon.
Earlier this year, Swedish battery maker Northvolt acquired a U.S. startup, Cuberg, which claims that its batteries sport 70 percent more range and storage capacity than lithium-ion batteries for the aviation sector, which is Cuberg’s primary target market for now.
Northvolt and Cuberg plan to scale the production of the new batteries quickly and start putting them in EVs. That would be a major breakthrough and not a moment too soon: Northvolt’s clients in Europe are eager to get their hands on some long-term battery supply for the millions of EVs they plan to be churning out soon. Whether they will succeed is still uncertain—for all the talk about major battery breakthroughs, lithium-ion technology continues to dominate the market still, in evidence that taking breakthroughs out of the lab and into the mass market takes time.