Tucson-based Sigma Technologies International Group has been awarded a $2.4 million grant from the U.S. Department of Energy for its work in capacitors.

Capacitors, like batteries, temporarily store electric charges. They are used in many electronic devices, including components in electric and hybrid cars.

“If you’re familiar with what a battery is, you’re halfway there,” said Steven Yializis, COO at Sigma Technologies. “The difference though is ... with a battery, it takes a long time to charge and quite a bit of time to discharge. So, when you need a lot of energy quickly, a battery doesn’t have the ability to do that. ... you rely on a capacitor.”

The problem with current capacitors is they have shape, size and temperature limitations. Sigma is working to fix that problem, making a material that can replace the main component of capacitors.

“We propose a capacitor ... (that would) increase the temperature resistance," Yializis said. "You reduce the size, the weight and also have a lot of flexible form factors.”

He said he hopes Sigma can change the design and capabilities of capacitors, fixing what is currently a major weak spot for hybrid and electric vehicles.

The grant money will allow the company to experiment and make prototypes of a new generation of capacitors that could make low-emission and zero-emission vehicles more reliable.