South Korean research team has developed super capacitor that does not lose its capacity even when it is used after being charged 10,000 times or more by using toilet paper and coffee. Because packing materials as well as electrodes and separation films are made out of paper, its flexibility is outstanding. It is expected that this super capacitor will be used for variety of flexible devices.
Korea Forest Research Institute (Director Lee Chang-jae), which is under Korea Forest Service, announced on the 27th that it co-developed environment-friendly paper super capacitor by using toilet paper and coffee as materials for electrodes, separation films, and packing materials with UNIST (Ulsan National Institute of Science and Technology, Chancellor Jung Moo-young).
Super capacitor is a high-output electric energy storage device that quickly saves electric energy and supplies high current either instantly or continuously. Active carbon, which is an electrode material, is very important in order to increase electrostatic capacity and improve performance.
Until now, harmful materials such as KOH and ZnCl2 were used as catalyst for active carbon. Because they are very corrosive, they reduce lifespan of manufacturing process.
Research team noticed the fact that porous active carbon is made by burning toilet paper that is made out of cellulose and used alkali metallic ion, which is in coffee, as a catalyst. It made electrode material by wetting toilet paper with coffee and drying toilet paper and heating it at 600°C for about 2 hours and made this material as an electrode after leaving this material inside of solution that is mixed with carbon nanotube and water.

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<Manufacturing of active carbon by using cellulose paper and coffee>

Research team also made separation films and packing materials with toilet paper. It made separation films and packing materials by filling gap of toilet paper with gel polymer electrolyte and PBMS polymer and completed super capacitor by covering separation films with electrodes and covering separation films with packing materials. It is shown that this super capacitor is very flexible and has excellent electric performance.
Every element including electrodes is made with paper which allows them to be easily bent and laid out. Electric chemical performance of this super capacitor also showed 130F/g of electrostatic capacity, which is twice higher than that of carbonized paper that is not wetted with coffee. Its stability is also excellent as capacity is maintained constantly even after charge and discharge of 10,000 times or more.
Research team published this technology on the most recent issue of ‘ACS Applied Materials and Interfaces’, which is an international journal published by American Chemical Society.
“35 to 40% of a plant’s biomass is composed of cellulose.” said Chief Researcher Lee Seon-young of Korea Forest Research Institute. “Cost of securing electrode materials can be greatly reduced when lumbers are used.”
“Active carbon manufacturing technology using paper that is wetted with coffee replaces harmful chemical materials with environment-friendly materials.” said Professor Lee Sang-young of UNIST. “Development of flexible paper super capacitor using toilet paper provides a new direction that can overcome limitations of current structure of batteries.”
Staff Reporter Shin, Seonmi |