Researchers at Linkoping University in Sweden have developed a 'power paper' that can store energy. The material consists of nanocellulose and a conductive polymer.
Unlike the batteries and capacitors currently on the market, power paper is produced from simple materials -- renewable cellulose and an easily available polymer. It is light in weight, requires no dangerous chemicals or heavy metals and it is waterproof.
One sheet of this new material, 15 cm in diametre and a few tenths of a millimetre thick, can store as much as 1F, which is similar to the supercapacitors currently on the market. The material can be recharged hundreds of times and each charge only takes a few seconds.
"Thin films that function as capacitors have existed for some time. What we have done is to produce the material in three dimensions. We can produce thick sheets," said study co-author professor Xavier Crispin. The material, power paper, looks and feels like a slightly plastic paper.
The structural foundation of the material is nanocellulose, which is cellulose fibres which, using high-pressure water, are broken down into fibres as thin as 20 nm in diametre. With the cellulose fibres in a solution of water, an electrically charged polymer, also in a water solution, is added.
The polymer then forms a thin coating around the fibres. "The covered fibres are in tangles, where the liquid in the spaces between them functions as an electrolyte," explained researcher Jesper Edberg.
The new cellulose-polymer material has set a new world record in simultaneous conductivity for ions and electrons, which explains its exceptional capacity for energy storage. The study was published in the journal Advanced Science.