Skip to main content

Next-Generation Batteries

Auburn researchers look beyond lithium ion for the next great battery

By Eduardo Medina

Exploding batteries create chaos.

That’s the headline Auburn University Assistant Professor Majid Beidaghi read in 2016 when Samsung’s newest cellphone, the Galaxy Note 7, began combusting inside the pockets and purses of people worldwide.

Surveillance footage showed people in restaurants jolting away from their phones as they emitted thick puffs of toxic smoke. Images showed charred bronze cellphone frames next to a man whose leg had just been scorched by the Samsung device, leaving him with second-degree burns.

A year later, hoverboards joined the lineup of gadgets susceptible to engulfing in flames, but these hazards are no surprise to Beidaghi. All wireless products have a common denominator in terms of power source, thus all wireless products are capable of an explosion, he said. In every camera, computer, tablet and cellphone lies this power source, and so too lies the cause for the vast number of explosions reported.

The culprit is lithium ion batteries.

Beidaghi and his team of Auburn researchers are spearheading the development of a new type of battery that will revolutionize all wireless products, and more importantly, end the flurry of headlines following another lithium ion battery explosion.

“We’re working beyond the lithium ion battery. It’s the best battery right now, but we’re developing a safer, more sustainable, multivalent battery,” Beidaghi said.

The idea behind Beidaghi group’s multivalent battery is being driven by earth’s most abundant metal — aluminum.

Armin VahidMohammadi, a graduate research assistant in Beidaghi’s lab, is among the researchers making aluminum batteries a reality. The setbacks accompanying lithium ion batteries are juxtaposed by aluminum’s benefits, he said; reactivity being an example.

“You can handle aluminum in the air, but you can’t do that with lithium because then...,” VahidMohammadi said before motioning his hands outwards, signaling an explosion.

The way a lithium battery discharges is that lithium ions are removed from the anode, or negative electrode, and lose electrons into an external circuit, which is where the functional work is done. Ions then move through an ionically conductive material, the electrolyte, and become embedded in the cathode or positive electrode. The failures of this system, which can result in explosions, come from charging too fast, physical damage or overheating.

Once a spark ignites, extinguishing the flames becomes difficult. Oxygen infiltrating the lithium fuels the fire because the oxidant is self contained in the battery. This, VahidMohammadi said, is why it’s important to make a battery without lithium and with aluminum — the latter is impervious to the effects of air, thus eliminating any chance of combustion.

The positives of aluminum also extend beyond safety. Batteries with a metal in the negative electrode are ideal because they give the most capacity and highest energy density. Lithium’s dangerous sensitivity and its tendency to grow dendrites that can cause a short circuit in the battery means using it as an anode is impossible, but aluminum is safe to use as an anode in an aluminum battery.

“Aluminum has the highest volumetric capacity among all metals, and we can use this property to make batteries that store a high amount of charge in a limited volume,” Beidaghi said.

The rewards brought on by aluminum’s charge density also present a problem. Because of its high charge density from three positive charges, aluminum interacts strongly with other similarly charged ions, preventing the intercalation of aluminum ions into the structure of most cathode materials.

“Not many people believed lithium batteries would work, and it ended up changing the world. So there is no scientific reason to think aluminum batteries won’t work either.”

If an aluminum battery system can be developed, then theoretically for each ion there will be three electrons, said Beidaghi; meaning an aluminum battery will be much more efficient and powerful than the lithium battery, which only gets one electron for each ion.

“If you increase the energy and power densities of batteries, you could be able to charge batteries quicker, and the charged battery could last much longer,” Beidaghi said.

The main obstacle in realizing an aluminum battery was finding a cathode material suitable for an aluminum battery — and the Auburn researchers found just that.

“We were working with a new family of materials called MXenes…We took one of the members of this family, used it as the cathode, and made a fully working battery,” VahidMohammadi said.

The Auburn researchers are the first to publish research highlighting the potential of MXenes as a cathode material for aluminum batteries.

“We have demonstrated that this can work, so it feels good,” VahidMohammadi said. “But it doesn’t come without challenges.”

With pioneering research comes unknown problems, and Beidaghi sees a parallel between the initial stages of their aluminum battery research and the research of lithium ion batteries in the 1970s, which was met with skepticism. The notion of lithium batteries was seen as farfetched and an unlikely development.

“Not many people believed lithium batteries would work, and it ended up changing the world,” Beidaghi said. “So there is no scientific reason to think aluminum batteries won’t work either.”

The surging electric vehicle market could be a prime platform for this research. Just like cellphones, these vehicles are powered by lithium ion batteries and are also prone to the same types of explosions; meaning people not only risk losing their phone in a pile of ash, but their $100,000 electric vehicle as well.

The exorbitant cost of these vehicles is largely because of lithium ion batteries, but having a cheaper battery could change that. Since aluminum is so abundant and easy to extract, aluminum batteries could potentially drive down the cost of luxurious Teslas.

“One important aspect of our work is the potential for making electric cars more affordable by making a safer and cheaper battery,” Beidaghi said.

Andrew Tormanen, an undergraduate researcher in Beidaghi’s lab, is responsible for changing the structures of materials on nano and micro scales in the research. He also regards developing next-generation batteries as a necessary progression needed in the electric vehicle market.

“In Europe, they’re phasing out gas vehicles for electric, so in the next five years, there’s going to be a rise in the demand for electric vehicles,” Tormanen said.

Just as electric vehicles are being heralded for their potential for increased sustainability, aluminum batteries could also be an equally advantageous product for the environment.

Recycling lithium from batteries is expensive and difficult, said Beidaghi, but recycling aluminum is something we have done for many years, and can continue to do. The plentiful amounts of the metal and its easy recyclability could be a huge benefactor for sustainability.

“If we continue on our current track in our research, we won’t be talking about batteries catching fire in the future,” Beidaghi said while pointing at his phone. “Difficulty is what we want. We are scientists, and we want to solve problems because we’re not afraid of them.”