How to Prevent Batteries From Exploding? Nanoparticles, Says Startup

By: Tekla S. Perry

still from a Nanom animated gif
Gif: Nanom
There’s a reason luggage on an airplane isn’t supposed to contain lithium-ion batteries—they have a tendency to explode into flames. That’s the same reason recreational vehicle manufacturers are embracing lithium iron phosphate, a battery technology with a lower energy density than lithium-ion, but without the fire risk, trading off capacity for safety.

Nanom (previously Greenvolt), a startup based in Silicon Valley and Iceland, says that tradeoff isn’t necessary, that you can have both safety and high energy density—plus a few other nice bonus features—through the use of nanoparticles. The company, founded in 2017, came out of stealth this month to hint at how its technology works, without revealing what company executives say are its trade secrets.

Nanom, to be clear, has no intention of making batteries itself, beyond those needed for tests and demonstrations. The company has developed a process for turning just about any typical battery material into nanoparticles. Its manufacturing line is small and energy-efficient enough that it can be set up in a trailer-sized unit and brought to a battery manufacturer’s site, company executives indicated, and its current pilot line in Croatia can produce kilograms of nanoparticles per hour.

The process starts with micron-sized particles of the material to be used. These go through a type of particle accelerator to be broken into nanoparticles. Next, the nanoparticles enter what the company calls the forge, where gases treat the surfaces of the particles to, among other things, make sure they disperse evenly in the solvents used in the manufacture of electrodes. This process can produce nanoparticles from 1000 nanometers down to 100 nanometers, plus or minus 50 percent, says Dave Tanner, Nanom senior technologist.

Using nanoparticles instead of the more typical micron-sized particles in battery manufacture has several advantages, Nanom CEO Armann Kojic explains. A main one is the fact that they will be safer, that is, less likely to catch on fire.

Tanner explains: “One of the big problems [with] lithium-ion batteries is that the electrodes aren’t uniform, because you don’t have good particle distribution of materials. Instead, there are regions of high and low resistance. That means that you get areas that are hot, damaging the battery.”

Damage can cause a short, igniting the lithium, or cause it to get hot enough that the solvent vaporizes and ruptures the battery, releasing flammable gases.  

A lot of people are working on solving this, Tanner pointed out, but they’re using chemical methods, involving etching and exfoliating layers of materials, to produce the nanoparticles. This approach, he says, is not cost effective.

Nanom’s process is largely mechanical, said Kojic. That’s both more efficient and more versatile—enabling the team to work with a greater variety of battery materials.

 “Our early goal was to bring nanotech to a level to be affordable for the industry to use widely,” says CTO Antonio Licitar.

In addition to making batteries safer, using nanoparticles can also increase energy density and lifespan dramatically. The reason? Smaller particles mean more surface area, better porosity, and better conduction for the same amount of material. Increased energy density allows manufacturers to choose battery chemistries that are inherently safer and perhaps more environmentally friendly that those in typical use today, Kojic said.

“We hope to make a huge impact on the environment,” he told me. “That’s been something in mind from the beginning of the company, to make a difference for the planet.”

Considering that lithium-ion batteries involve materials that are both toxic and in short supply (most use cobalt in the cathode), Kojic said, “If we continue at the same rate that we are consuming some of these materials today, we will begin to have shortages. If we can get more out of the materials by using them more effectively or be able to [give other] materials better performance, we’ve helped the situation.”

Nanom’s team sees another intriguing possibility for nanoparticle batteries, though not one likely to be commercialized in the near future. Because the technology can be so safe, stable, and have long cycle life, Kojic says, it could be used in structural batteries. Those are batteries embedded into the wall of the house or car or hull of a boat. The company is using the latter application as a demonstration project.

“We could redesign products around the user, instead of the other way around, designing devices around batteries. For example, our phones are just glorified battery holders.”

What’s next for Nanom? Stay tuned, Kojic says, for announcements about partners coming in from the battery and automotive industry later this year.

This article originally appeared in IEEE Spectrum on 15 April 2021.