Power Paper, created by the researchers of Sweden’s Linköping University, is showing an outstanding ability in storing energy, which can later be used to recharge devices.
To meet the ever-increasing energy demands of our society, we need two kinds of devices – the first kind are the ones that can generate energy from renewable sources and the second are the ones that can store the generated energy as most of our renewable energy sources are not regular. They are either seasonal or directional and altogether, they are variable and intermittent. So, we need better energy storage devices to compensate for the intermittency of our renewable energy sources and realise the 100 percent renewable energy dream as soon as possible.
Scientists at the Organic Electronics Laboratory of Linköping University, Sweden, came up with an innovative solution by creating the so-called Power paper from nano-fibrillated cellulose and a conductive polymer. Unlike the regular capacitors and batteries, which require toxic materials and heavy metals, the power paper is made from renewable cellulose and readily available polymer.
The cellulose fibers were subjected to high-pressure water to break them down into nanofibers as thin as 20nm in diameter and get the electrically charged polymer form a thin coating around the fibers. ”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 has recently completed his doctorate.
The material, just like a regular paper pulp, has to be dehydrated to make it into a power paper. A circular sheet of 15cm diameter and a few tenths of a millimetre thickness can store around 1Farad, which is as good as the storage capacity of supercapacitors available in our markets today. The nano paper takes only a few seconds to get fully charged and it can be recharged for hundreds of times.
The power paper, which is very light in weight and waterproof, gives a feeling of plastic when touched. Delighted by their invention, the researchers even managed to create a Power paper origami swan, which stands out like a testament to the strength and flexibility of the paper.
The project has been financed by the Knut and Alice Wallenberg Foundation since 2012. “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. He, along with the researchers from KTH Royal Institute of Technology, Innventia, Technical University of Denmark and the University of Kentucky, who also took part in the development of the paper, co-authored the results of the invention as an article, which was published in the journal Advanced Science.
The invented nano paper, which has high electronic and ionic conductivities, currently holds 4 world records –
- The highest charge and capacitance in organic electronics, 1Coulumb and 2Farad.
- The highest measured current in an organic conductor, 1Ampere.
- The highest capacity to simultaneously conduct ions and electrons.
- The highest transconductance in a transistor, 1Siemen.
With such remarkable abilities, it sure has the potential to revolutionise the field of renewable energy storage as it has also opened the doors to research for even higher capacities.
News has it that the researchers have also received funding to develop a technology that can mass-produce the power paper. ”Together with KTH, Acreo and Innventia we just received SEK 34 million from the Swedish Foundation for Strategic Research to continue our efforts to develop a rational production method, a paper machine for power paper,” says Professor Magnus Berggren, director of the Laboratory of Organic Electronics at Linköping University.