Today, lithium-ion batteries are the backbone of most electronic devices, including electric vehicles.
Yet despite all their revolutionary advantages, these batteries still have an inherent flaw: the dendrites make it less stable. These thin, treacherous, tree-like pieces of lithium form sharp spikes that eventually puncture the battery, causing shorts and other problems.
The dendrites not only make the lithium-ion battery less stable, but also less durable.
To put it mildly, they have ample room for improvement.
Scientists sought to understand how lithium dendrites form to see how to produce a more stable and longer-lasting battery for electric vehicles.
Today, researchers atHarvard University say they have the answer: a lithium-metal battery made of a solid-state metal material instead of lithium-ion. A stable battery, which eliminates annoying dendrites and offers greater solidity and durability than a battery made of liquid or graphite materials.
Much better, for more reasons
“Our multilayer design has the structure of a less stable electrolyte sandwiched between more stable solid electrolytes, which prevents the growth of lithium dendrites,” the scientists say in the new study published in Nature.
A stable and “self-healing” battery
Making the battery out of mostly solid materials helps prevent dendrite formation in more ways than one. Mechanically, it is much easier to break a thin metal or ceramic shell than to penetrate, for example, a solid battery anode. This project goes a step further by chemically accounting for any cracks with “dynamically generated decompositions” which fill and block potential dendrites.
How is the stable metal lithium battery made?
Think of the new stable battery as a hamburger with lettuce and tomato: the bread is the lithium metal anode, the lettuce is the graphite, the tomatoes are the first electrolyte, and the bacon is the second electrolyte. Add another layer of the first electrolyte, cover it with a cathode and enjoy your meal.
What could change when switching from lithium-ion to lithium-metal batteries?
In a perfect world the lithium-metal battery is lighter, more powerful, longer lasting. Unfortunately, until now it was not possible to obtain a stable version. The reduction or elimination of dendrite formation is fundamental to any of these projects, it is she who greatly reduces any negative results. Harvard scientists tested their battery for over 10.000 charge cycles, rivaling a traditional (fossil fuel) car, but they didn't stop there.
They found that after these 10.000 cycles their design still retained 82% of its charge!
With this stable battery an electric car can last as long as and longer than a "fossil" one
This battery technology could extend the life of electric vehicles to that of gasoline-powered cars, from 10 to 15 years, without the need to replace the battery. With its high current density, the battery could pave the way for electric vehicles that can fully charge within 10 minutes.
From the Harvard University press release
What does all this mean for the future of batteries and electric vehicles?
If the design works as intended, it can open the lithium-metal battery door on the market by itself. For electric vehicles, the cost of batteries alone is almost dominant. Reducing breakdowns and weight would create huge savings.
“A lithium-metal battery is considered the Holy Grail for battery chemistry due to its high capacity and energy density,” he says Xin Lee, Harvard researcher. “This proof-of-concept project shows that solid-state lithium-metal batteries could be competitive with commercial lithium-ion batteries.”
