The world has too many nasty old cigarette butts. On the other hand, the world could use some supercapacitors, the high-tech replacements for batteries that could potentially charge in seconds. Scientists in South Korea have found a simple process to turn used cigarette filters into high-performing material that works better than graphene or carbon nanotubes in supercapacitors.
In case you haven't been following the supercapacitor hype, they're devices that store energy in electrical charges rather than chemical reactions, as batteries do. That means supercapacitors can charge and discharge much faster than batteries. The reason you don't have a lightning fast supercapacitor in your laptop, though, is because they're huge. They have largely been relegated to industrial uses so far, like storing the energy from wind turbines, but scientists are always looking for new ways to make better supercapacitors.
One unexpected source for new supercapacitor material is used cigarette filters, which currently do little but litter our sidewalks and parks. In a study published in Nanotechnology, scientists in South Korea report how to treat filters to help make supercapacitors.
The material inside cigarette filters is a synthetic fibre called cellulose acetate that, when heated in the presence of nitrogen, turns into a carbon-based material full of pores. The pores contribute to its high surface area, making it good for supercapacitors. When the team tested it for how well it charged and discharged electrons, they found it worked better than commercially available materials -- as well as graphene and carbon nanotubes, as reported in previous studies.
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