The researchers claim that one sheet, 15cm in diameter and a few tenths of a millimetre thick can store as much as 1farad, which is similar to the supercapacitors currently on the market. They also say that the material can be recharged in seconds, hundreds of times.
Xavier Crispin, professor of organic electronics at Linköping University, said: “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.”
Unlike the batteries and condensers currently on the market, power paper is produced from simple materials, is light in weight, requires no dangerous chemicals or heavy metals and it is waterproof.
To form the power paper, cellulose fibres are broken down into fibres as thin as 20nm in diameter, using high-pressure water. Then an electrically charged polymer, also in a water solution, is added that then forms a thin coating around the fibres.
Jesper Edberg, the doctoral student who conducted the experiments, explained: “The covered fibres are in tangles, where the liquid in the spaces between them functions as an electrolyte,”
The cellulose-polymer material has set four world records Highest charge and capacitance in organic electronics, 1Coulomb and 2F; Highest measured current in an organic conductor, 1A; Highest capacity to simultaneously conduct ions and electrons; and Highest transconductance in a transistor.
The next challenge is to develop an industrial-scale process for producing the power paper, which has to be dehydrated like regular paper pulp.
