Researchers at Linköping University’s Laboratory of Organic Electronics, Sweden, have developed power paper – a new material with an outstanding ability to store energy. The material consists of nanocellulose and a conductive polymer. The results have been published in Advanced Science.
One sheet, 15 cm in diameter and a few tenths of a millimetre thick can store as much as 1 F, 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,” says Xavier Crispin, professor of organic electronics.
The material, power paper, looks and feels like a slightly plasticky paper and the researchers have used one piece to make an origami swan – which gives an indication of its strength.
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 diameter. 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,” explains Jesper Edberg, doctoral student, who conducted the experiments together with Abdellah Malti, who recently completed his doctorate.
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, it requires no dangerous chemicals or heavy metals and it is waterproof.
The new power paper is just like regular pulp, which has to be dehydrated when making paper. The challenge is to develop an industrial-scale process for this.
[Image: Linköping University]