The consumer demand for seamless, integrated technology is on the rise, and with it grows the Internet of Things, which is expected to grow to a multitrillion-dollar market by 2020. But in order to develop a fully integrated electronic network, flexible, lightweight, rechargeable power sources will be required.
A team of researchers from Ulsan National Institute of Science and Technology is looking to address that issue, developing inkjet-printed batteries that can be modified to fit devices of any shape and size. The team reports that the newly developed inks can be printed onto paper to create a new class of printed supercapacitors.
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This from Ulsan National Institute of Science and Technology:
The process involves using a conventional inkjet printer to print a preparatory coating—a ‘wood cellulose-based nanomat’—onto a normal piece of A4 paper. Next, an ink of activated carbon and single-walled nanotubes is printed onto the nanomat, followed by an ink made of silver nanowires in water. These two inks form the electrodes. Finally, an electrolyte ink—formed of an ionic liquid mixed with a polymer that changes its properties when exposed to ultraviolet light—is printed on top of the electrodes. The inks are exposed at various stages to ultraviolet irradiation and finally the whole assembly is sealed onto the piece of paper with an adhesive film.
The process results in a printed supercapacitor with good mechanical flexibility and reliable electrochemical performance. The team used the printed supercapacitor to make a ‘smart glass’ that responded to a temperature stimulus. The supercapacitor was printed onto the glass in the shape of the words ‘hot’ and ‘cold’. When the glass was filled with hot or cold liquids, a red LED lamp lit up the word ‘hot’ or a blue LED lamp lit up the word ‘cold’ respectively.
