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Troublesome green algae turned into green battery

2010-03-15

The unwanted blooming of the green alga Cladophora along the Baltic coast, and elsewhere in the world, may not only be a bad thing. A research team at Ångström Laboratory in Uppsala has discovered that the extremely special nanostructure of the cellulose in these algae serves extremely well as a basis for new, environmentally friendly batteries.

“This opens new potential for large-scale production of environmentally friendly, cost-effective, and light-weight energy storage systems,” says Maria Strømme, professor of nanotechnology.

“This algal cellulose has a distinctive structure, with a very large surface. By covering it with a thin layer of a conductive polymer, we have managed to make a battery that weighs next to nothing, while setting a world record for charging capacity and charging time for polymer-cellulose-based batteries,” says Gustav Nyström, a doctoral candidate in nanotechnology.

In recent years the development of new cellulose-based polymers for battery applications has been extensive, but their charging properties have not been good enough. But no one had previously used algal cellulose. Researcher Albert Mihranyan and Professor Maria Strømme at the Division of Nanotechnology and Functional Materials at Ångström Laboratory have been working for several years with cellulose from Cladophora algae in pharmaceutical applications. This unique cellulose, whose nanostructure is entirely different from that of terrestrial plants, has been shown, for instance, to function well as a thickening agent in pharmaceuticals and as a binding additive in foods. It was precisely the large surface structure that prompted these scientists to look at its energy-storing properties.

“We have long thought that it would be great to be able exploit the material in these algal blooms and turn it into something good – and we have succeeded. These battery studies have been special and truly interdisciplinary. They grew out of a collaboration with the chemist Leif Nyholm. Cellulose pharmacists, battery chemists, and nanotechnologists were all needed for us to develop this new battery material,” says Maria Strømme.