Ultrasounds might lead fires due to upcoming battery defects

It’s hard to imagine a world without the lithium-ion batteries that power today’s laptops and mobile devices, but the technology has its limits. One way researchers are working to break the energy density barrier and significantly extend the battery life of these devices (and many others) is to bring pure lithium metal into the mix. A new battery architecture from researchers at the University of California San Diego offers a solution to a major drawback of this approach, using sound waves to prevent dangerous surges that would cause lithium metal batteries to fire and fail. Are.

Some battery researchers consider lithium metal a “dream material” because of its incredibly high energy density. If we used it as an anode component instead of the copper and graphite we use today, we could theoretically double the capacity of today’s best lithium batteries. That means electric cars that double up on a single charge or smartphones that last for days.

So there are many reasons to pursue this battery architecture, but lithium metal also has some problems. As the lithium ions move between the lithium metal cathode and anode, they pass through the stable electrolyte liquid, causing the lithium to distribute unevenly and accumulate at the anode. This leads to the development of tentacle-like structures called dendrites, which in turn causes the battery to deteriorate quickly or cause a short circuit and the battery to catch fire.

We have recently seen some amazing breakthroughs that can overcome this problem. One solution by the MIT scientists uses a solid electrolyte instead of a liquid, which helps avoid unwanted reactions from lithium metal. Another study we reviewed this week from researchers in Australia uses a unique blend of materials to form a protective layer on the surface of a lithium metal anode, making dendrites less likely to form.

Researchers at the University of California at San Diego consider the static nature of the liquid electrolyte one of the major challenges in modern lithium metal battery designs To change the nature of this phenomenon, the team turned to ultrasound, which actually plays a role in modern smartphones. Uses sound waves to filter cellular signals, filter and identify voice calls or data.

“It was advances in smartphone technology that actually allowed us to use ultrasound to improve battery technology,” says James Friend, professor of mechanical and aerospace engineering and co-author of the study The team created a small ultrasonic device and incorporated it into a lithium metal battery . There, it sends high-frequency sound waves of 100 million to 100 million Hz through the liquid electrolyte, causing it to flow rather than remain static Instead of heterogeneous bodies, this allows neat and uniform deposition of lithium on the anode and avoids dendrite formation.

In testing, the team’s lithium metal battery proved stable over 250 charge cycles, charging from zero to 100 percent in just 10 minutes

Ping Liu, professor of nanoengineering and senior author of the study, says, “This work to simultaneously build fast-charging high-energy batteries “is fun and effective.”

While the research team focused directly on lithium metal batteries, they say the ultrasonic device can be easily adapted to other types of batteries as well. They tested it as part of a lithium-ion battery that lasted 2,000 cycles and see great potential in it.

“The next step will be to integrate this technology into commercial lithium-ion batteries,” says Haodong Liu, co-author of the paper.

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