UToledo Engineer Eyes New Batteries for Use in Oceans, Outer Space

UToledo Engineer Eyes New Batteries for Use in Oceans, Outer Space

A robust battery that can provide power for long-term, unattended operations is a critical component for missions in remote and harsh environments, such as deep in the ocean or high in outer space.

It's a key reason engineers are drawn to radiovoltaics, a category of battery that converts nuclear radiation into electrical energy and can last months to years without recharging.

The University of Toledo is collaborating on a $2.8 million project to advance the technology under the Defense Advanced Research Projects Agency (DARPA) of the U.S. Department of Defense. The research team, led by the University of Missouri, is developing micro-scale radiovoltaic devices suitable for applications like buoys, spacecraft and remote sensors.

"We're working under DARPA's Rads to Watts program, which explores new approaches for directly converting nuclear radiation energy into electricity," said Dr. Raghav Khanna, the Leidich Family Endowed Professor of Power Systems in the College of Engineering. "Our goal is to produce 10 watts of electricity per kilogram of mass, which is a significantly higher power density than existing radiovoltaic devices."

Khanna brings to the project an expertise in energy conversion systems, which is a wide-reaching specialty covering the generation, distribution and transmission of power. He is also developing expertise in the domain of materials through extended collaborations with colleagues in UToledo's Department of Electrical Engineering and Computer Science and Department of Physics and Astronomy.

He compared radiovoltaics to photovoltaics, known colloquially as solar cells, in that they utilize a semiconductor to convert a non-electrical energy source into electricity. Whereas a solar cell is powered by photons emitted by the sun, radiovoltaic devices are powered by charged particles emitted in the decay of a radioactive material.

The research team is specifically pursuing devices that utilize gallium oxide as a semiconductor to facilitate the conversion of radiation to electricity.

"Gallium oxide is more radiation tolerant than some alternatives being used in radiovoltaic devices," Khanna said. "That means they have the potential to work more efficiently and more effectively, which in turn allows for a longer operating life."

Khanna will lead a team of two doctoral and one undergraduate students on the project at UToledo, which is collaborating on the project alongside Pennsylvania State University, the University of Houston and the Naval Research Laboratory.

The UToledo team will take the lead on the finite element modeling that will simulate how the devices they design will operate. These simulations will ultimately inform which models go on for fabrication.

"When a simulation works, we'll hand that recipe off to our collaborators," Khanna said. "We're anticipating a lot of iteration between the teams in order to optimize the performance of the device."