Paper-thin Batteries Made from Algae

[Bruce Nunnally]

Imagine wrapping paper that could be a gift in and of itself because it lights up with words like "Happy Birthday." That is one potential application of a new biodegradable battery made of cellulose, the stuff of paper.

Scientists worldwide are striving to develop thin, flexible, lightweight, inexpensive, environmentally friendly batteries made entirely from nonmetal parts. Among the most promising materials for these batteries are conducting polymers.

However, until now these have impractical for use in batteries — for instance, their ability to hold a charge often degrades over use.

Easy to make

The key to this new battery turned out to be an often bothersome green algae known as Cladophora. Rotting heaps of this hairlike freshwater plant throughout the world can lead to unsightly, foul-smelling beaches.

This algae makes an unusual kind of cellulose typified by a very large surface area, 100 times that of the cellulose found in paper. This allowed researchers to dramatically increase the amount of conducting polymer available for use in the new device, enabling it to better recharge, hold and discharge electricity.

"We have long hoped to find some sort of constructive use for the material from algae blooms and have now been shown this to be possible," said researcher Maria Strømme, a nanotechnologist at Uppsala University in Sweden. "This creates new possibilities for large-scale production of environmentally friendly, cost-effective, lightweight energy storage systems."

The new batteries consisted of extremely thin layers of conducting polymer just 40 to 50 nanometers or billionths of a meter wide coating algae cellulose fibers only 20 to 30 nanometers wide that were collected into paper sheets.

"They're very easy to make," Strømme said.

Read more: LiveScience.com