Engineering students’ seawater battery project wins first at Go Green North America

Lithium is a metal that dominates the battery industry. Lightweight and powerful, lithium-ion batteries are used in laptops, phones, scooters, electric toothbrushes and other consumer electronics. 

Global lithium mine production nearly quadrupled from 2010 to 2021, according to Statista. Demand is poised to increase even more as electric vehicles—the largest type of consumer electronics—become common goods. 

All this lithium mining has consequences, says Alexandra Berkova, a senior at the College of Engineering and Computing. 

"Lithium is becoming a very scarce resource,” Berkova says. “And on top of that, there’s a lot of unethical mining for lithium in Africa.” 

Berkova and seniors Ana Claus and Amanda Perez are innovating a way to alleviate lithium demand. The three mechanical engineering students are prototyping a seawater battery that would operate using sodium, a metal that can be pulled from the ocean’s sodium chloride molecules. The sodium would replace lithium in these batteries.

This seawater battery design earned first place at Schneider Electric’s Go Green for North America, a continental-wide clean energy competition. The FIU team advances to the Go Green global competition on June 21 for a chance to win 10,000 Euros.

“Their idea was completely unique and groundbreaking," says Monica Arriaga, a manager at Schneider who coached the Panthers. “The fact that they were pursuing a prototype was impressive. Maybe one in every 10 teams does that."

The students plan to have a working prototype in December. Their goal: use the battery to charge a phone.

Can batteries be better where it's wetter?

If successfully forged, the seawater battery would have several benefits, beginning with the fact that it contains no toxic metals.

“You can choose almost any two metals and make a battery,” says Professor Bilal El-Zahab, an expert in emerging battery technologies at the university and an advisor to the FIU team. "Sodium is a light, energy-dense and abundant material that we can work with."

The battery could be coupled with offshore wind turbines and solar panels, El-Zahab says. This could become a useful store of energy for islands that lack large power grids. 

The battery should also be highly efficient over time since it would constantly obtain sodium from the ocean. Lithium batteries usually aren't replaced with fresh lithium, leading to something called electrode corrosion.

“A common way that people experience electrode corrosion is when they buy a laptop," El-Zahab says. "Let’s say you buy a laptop today and it has a seven-hour life. You might notice that in a couple of years, it only lasts three hours. This is because the lithium-storing electrode corrodes as you use it."

Turning a plan into a reality

Seawater batteries aren't new to the scientific community, El-Zahab says, but they have yet to be commercially viable.

“If you fix a lot of issues, which is why the battery doesn’t yet exist, this could be a very stable performance type of battery,” El-Zahab says. "These problems are what the students are trying to innovate on and improve.” 

This type of battery needs to be completely waterproof. Sodium as an element is highly reactive with water. If you tossed sodium in the ocean, there would be a small explosion. 

“We are making the battery from scratch,” Perez says. “Instead of using cake powder to make the cake, we are trying to figure out how much flour to begin with."

Berkova, a former English major, hopes that her team's success can inspire other young women to pursue careers in engineering. Women consistently comprise the minority of mechanical engineering majors compared to men.

"When I talk with people, they say ‘Oh, I’m not good at math or science,'" she says. "But I don’t think that should stop them. I want more to just try it out like I did."