Researchers at LinköpingUniversity's Laboratory of Organic Electronics, Sweden, have developed what they call “power paper” – a new material that consists of nanocellulose and conductive polymer, capable of storing energy.
One sheet of power paper is 15 cm in diameter, a few tenths of a millimeter thick, and capable of storing as much as 1 farad, similar to that of supercapacitors currently on the market. The team’s material takes a few seconds to re-charge and can be re-charged up to hundreds of times. The material the researchers used to create the power paper, looks and feels like a strong sheet of plastic paper.
“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 and co-author of the team’s article.
The paper is based on nanocellulose, cellulose fibers that are broken down into fibers about 20 nm in diameter once in contact with high-pressure water. With the cellulose fibers in a solution of water, an electrically charged polymer that is also in a water solution is added to the mix which is when the polymer forms a thin coating around the fibers.
"The covered fibers are in tangles, where the liquid in the spaces between them functions as an electrolyte," says Jesper Edberg, a doctoral student who conducted the experiments.
The new cellulose-polymer material has set a new world record in simultaneous conductivity for ions and electrons, part of the reason why the team feels it is contains a high capacity for energy storage.
Unlike batteries and capacitors on the market today, power paper is constructed with simple and readily available materials, is waterproof, and does not require the use of harmful chemicals.
The team will face its next challenge in the development process – figuring out how to develop an industrial-scale process for this. Linköping University has just received funding to work on a paper machine that will produce power paper.