Bettering batteries

Few things are more frustrating than when a laptop dies in the middle of a class lecture or an iPod fails to last the whole flight home. But university researchers are looking to combat this persistent problem, using a special plant virus to help sustain battery life.

For two years, researchers from the engineering school and the agriculture and natural resources college have been developing smaller, more efficient and cost-effective batteries that could have a 10-fold increase in energy capacity over a commercial battery.

"If we can show that these batteries are as powerful or more powerful than standard AA batteries and are smaller in weight and size, then ultimately you have a technology that produces more cost-effective power and longer-lasting batteries for future applications," electrical engineering professor Reza Ghodssi said.

Although the virus is well known for destroying tobacco plants and other crops, plant science and landscape architecture professor James Culver grows the virus — known as the tobacco mosaic — in a controlled environment on the campus.

He said using this virus specifically for their research was necessary due to its unique shape.

"The virus has this rod shape, and we've genetically engineered it so we can attach it to this current collector at one end," Culver said. "What that allows you to do is pack a lot more surface area into a given area of the battery, so you can pack more potential energy into that little area."

Ghodssi, who worked with graduate student Konstantinos Gerasopoulos on the project, said increasing the surface area inside the battery helps increase the power.

"Once you have more surfaces, then you have more reactions taking place," Ghodssi said. "The output has higher capacity and can last longer."

In addition, Culver said the virus was engineered from a special protein that attracts metal ions; this allows researchers to apply a nickel coating to the virus that acts as an electrical current collector and increases its power.

Chemical and biomolecular engineering professor Chunsheng Wang further increased the power of the battery by coating the metal virus rods with a silicon base that stabilizes the structures and works better with the battery electrode.

Wang said that as electronics — such as cell phones, notebooks and MP3 players — continue to shrink in size, the demand for smaller and more lightweight power sources increases.

"For any application where you need a small-sized battery, you can use this [battery]," Wang said. "With our new device, we can shrink the size but still provide energy and high power."

The researchers are working on improving the battery by making the virus form multidimensional shapes to even further increase the surface area on the battery, Ghodssi said, adding it most likely would not be ready for mainstream use for at least 10 years.

Culver said the research wouldn't have been possible without bridging the different colleges at the university.

"It's a real key theme," Culver said of the interdisciplinary effort. "I don't think you can do these things unless you have a lot of people with diverse backgrounds."

saravia at umdbk dot com