Seaweed capacitors

New materials for advanced electronics are usually expensive, high-tech substances. But a team of researchers in France has shown that energy-storage components called supercapacitors can be made from a remarkably cheap and humble material: baked seaweed.

Francois Béguin of the CNRS Research Centre on Divided Matter in Orléans, France, and his co-workers say that seaweed, when burned to a charcoal-like form, is just the right stuff for making the electrodes in state-of-the-art supercapacitors. It performs as well as the carbon-based substances currently used in commercial devices, the researchers say.

The seaweed-derived polymer that Béguin has hit upon, called alginate, is non-toxic, and is widely used as a thickener in foods and cosmetics: 20,000 tonnes of it are extracted from seaweed for this purpose every year. This makes the material very cheap.

Supercapacitors provide an alternative to batteries for power storage in portable electronics. They consist of a pair of plates, or electrodes, loaded with electrical charge that can be subsequently tapped, producing a current.

Source: nature.comAdded: 4 August 2006