INQUIRING MINDS

Sustaining the Battery Surge

By Kenneth Mashinchi

With the demand for batteries only expected to rise, SJSU Assistant Professor Dahyun Oh is exploring ways to make them sustainable and longer lasting.

Dahyun Oh

Batteries are integral to our lives, from our phones and laptops to cars. As rechargeable batteries get older, they retain less power — the battery life on a smartphone is likely not at the same 100% charge as when it was first used, even if the phone indicates it is fully charged.

Assistant Professor Dahyun Oh of San José State University’s Charles W. Davidson College of Engineering is trying to understand why that is, while also exploring new ways to build the next generation of batteries that will last longer using sustainable materials.

“Sustainability is a key issue for us and future generations,” says Oh. “Academic research isn’t for profit — we really care about building a system that is more sustainable. We have a long-term vision to solve the longer generational problems, so it will eventually have a greater impact on humanity.”

Dahyun Oh is seen behind the clear case while her lab partner has their hand inserted in the arm holes of the case.

Students get hands-on experience in Oh's lab, experimenting with water or bacteria as power conductors for alternative batteries. Photo by Robert C. Bain.

Two wires pinching a metal screw inside a machine.

Equipment in Oh's lab allows the team to simulate thousands of hours of battery life into days and calculate the amount of power the alternative batteries contain. Photos: Robert C. Bain.

Alternatives to current lithium-ion batteries may contain solid or water electrolytes, which are inherently safer but have limitations in battery life cycle and power performance. Oh and her team of SJSU student researchers are exploring different ways to address these issues. By using a device that simulates battery usage — condensing hundreds or thousands of hours of battery life into days — Oh can decipher how the flexible structure and materials to produce power work and how long it will last. Ultimately, it could reveal what internally causes our typical lithium battery’s power to degrade.

Oh’s research involving water as a potential electrolyte that can be used as a power source seeks to understand why water-in-salt electrolytes (WiSE) struggle with instability, while exploring whether adding an additional layer on battery materials could help make this a more viable power option. Oh is also using bacteria to produce battery conductors, drawing on the natural process of living organisms forming fossils as they become flexible composite electrodes.

The students in her lab relish the opportunity to be on the front lines of designing the batteries of the future.

“It’s really unexpected,” says Danitza Hernandez, ’25 Materials Engineering. “Everyone else is doing their master’s program, and I feel very honored that Professor Oh allowed me to join this program without having any experience at all except general education classes. I never thought I would learn or even touch equipment.”

“Working with Dr. Oh is a great opportunity as a student who did not have prior experience in batteries,” says Ali Fakhry, ’23 MS Materials Engineering. “Hopefully we will be able to move forward and upgrade batteries and get an upper hand when we go into the battery industry.”

“Academic research isn’t for profit — we really care about building a system that is more sustainable. We have a long-term vision to solve the longer generational problems, so it will eventually have a greater impact on humanity.”

— Dahyun Oh

Oh says offering undergraduate students like Hernandez crucial research opportunities so early in their academic careers makes SJSU more competitive than other research-active institutions.

“Undergraduate students play a big role,” Oh says. “Although they don’t have as much experience as students with a higher level of training in academia, it certainly accelerates their training in education by starting early. I think it helps enhance science in the United States as well.”

Want to learn more?

Visit Oh's Energy Materials Lab to explore ongoing research.

Top photo: Robert C. Bain.