Driving Change

Electric cars were once a futuristic fantasy straight out of “The Jetsons.” But now, electrical vehicles have started showing up on more roads. And in more advanced ways: The Tesla Model S battery pack is now composed of nearly 8,000 cylindrical lithium-ion batteries — each about the size of a AA battery — underneath the vehicle to provide 345 miles of charge.

Powering cars with lithium-ion batteries is a great technological feat — but these batteries are also known to catch fire. While this is just one issue and electric vehicles have been proven to be equally as safe overall as traditional vehicles, decreasing risk is key to developing a more electric, environmentally friendly future.

Enter University of Akron Polymer Science Associate Professor Yu Zhu and his team of 10 graduate students who are working in the university’s nanomaterials and organic electronics lab to improve the safety of lithium-ion batteries.

These batteries are composed of three parts: a positive electrode, a negative electrode and a surrounding electrolyte solution that conducts electricity. During a high-impact collision like a car accident, the electrolyte solution is not a strong enough insulator to prevent the positive and negative electrodes from coming into contact with each other, which heats them up and short-circuits them, potentially catching on fire.

After about six months working specifically on the electrolyte solution research, Zhu and his team made their most exciting breakthrough in 2017: They created a shear-thickening effect in their electrolyte solution.

“We felt very happy and very lucky,” says Zhu. “We didn’t have to spend years to get [results], we spent a couple months.”

A shear-thickening fluid — also known as a dilatant — is like Oobleck, the slime you might have made in middle school that acts like a liquid when you dip your hand in it but turns solid-like if you punch its surface. By creating a shear-thickening electrolyte solution, Zhu and his team’s aim is to minimize, if not completely eradicate, the incidence of electrode collision and thus electric car fires. The shear-thickening electrolyte solution that is normally liquid becomes solid-like upon impact, preventing the positive and negative electrodes from touching each other and short-circuiting into a fire. Since their discovery, the team has focused on making the solution as lightweight and effective as possible.

Zhu’s team includes recent Ph.D. graduate Kewei Liu — a primary author of the team’s study that was recently published in the Journal of Power Sources — and Ph.D. candidate Chung-Fu Cheng. Working in Zhu’s lab to gather information for lithium-ion battery research and conduct experiments for Zhu’s electrolyte solution, Cheng learned a lot from Zhu and even got advice about his plans to conduct independent scientific research.

“In every discussion he gives me a lot of suggestions on my future plans,” Cheng says. “He really puts me in his shoes. I appreciate his advice style and his suggestions to me, not only in research but also how to become a very successful scientist.”

Zhu hopes to get these breakthroughs out of the lab and into the real world. He’s created a company, Akron PolyEnergy, to help get lab-developed technology on the market and into the cars we drive. Perhaps one day electric cars won’t seem so futuristic and will be even safer, too.

“The electrical vehicle is a revolutionary technique,” says Zhu. “We want a clean vehicle; we want a more drivable vehicle. To make it better, we need a better battery.”