Solid-state lithium metal batteries have potential to out-perform lithium-ion in terms of capacity and density, but for one sticky problem. Their anodes grow needle-like dendrite structures that penetrate the barrier, and short circuit the cathode. Researchers at Harvard say they cracked the code with a lithium metal sandwich battery. This sounded tasty and we decided to investigate.
Secret Sauce Inside Lithium Metal Sandwich Battery
“A lithium-metal battery is considered the holy grail for battery chemistry, because of its high capacity and energy density.” So says Xin Li, associate professor of materials science at Harvard John A. Paulson School of Engineering and Applied Science. “But the stability of these batteries has always been poor.”
Xin Li and his colleagues clearly regarded this as a challenge. They built a high density lithium metal sandwich battery, and paired it with ‘a commercial high energy density cathode’. The result was a novel lithium metal battery with an ability to charge and recharge at least 10,000 times.
The potential of this new invention for electric vehicles is far-ranging, according to the announcement in the Harvard Review we link to below. The new battery could extend the lifetime of electric cars to 15 years without battery replacements. And fully charge in 10 to 15 minutes as an added bonus.
We Could Dine Off This Story For a Long Time
When people ask us ‘why batteries’, we reply because they are interesting, and we get a confused signal back. But if we relayed this story over dinner to friends, they might invite us to return for an update. That’s because Xin Li asks us to imagine his battery as a bacon, lettuce and tomato sandwich.
The dendrites grow through the graphite and the first electrolyte, but are unable to penetrate the second electrolyte. “Our multi layer design guides and controls the growth,” Xin Li explains. “Until it reaches a barrier that is too tight for the dendrite to drill through, and so the dendrite growth is stopped.”
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