South Korea
It is estimated that 840,000 tons of cigarette butts wind up as toxic trash worldwide every year, and with 9 trillion filtered cigarettes expected to be consumed worldwide by 2025, the global environmental burden of cigarette filters is significant.
However, a research team from Seoul National University in South Korea has developed a way to turn cigarette butts into energy storage devices that outperform commercially available ones. The scientists transformed the cellulose acetate fibers in cigarette filters into a carbon-based energy storage material using a simple, one-step burning technique called pyrolysis.
The carbon-based material was tested to see how well it could adsorb electrolyte ions and then release them. The material stored more electrical energy than commercially available carbon, graphene and nanotube capacitors.
The scientists reported their findings in the IOP Publishing journal Nanotechnology. They say the high performing material can be integrated into computers, handheld devices, electric vehicles, and wind turbines to store energy.
“A high performing supercapacitor material should have a large surface area, which can be achieved by incorporating a large number of small pores into the material,” says Professor Yi. “A combination of different pore sizes ensures that the material has high power densities, which is an essential property in a supercapacitor.”
“Numerous countries are developing strict regulations to avoid the trillions of toxic and non-biodegradable used cigarette filters that are disposed of into the environment each year. Our method is just one way of achieving this,” says co-author Professor Jongheop Yi of Seoul National University.
A supercapacitor has many advantages over a battery. It can be charged and discharged virtually an unlimited number of times. Unlike the electrochemical battery, which has a defined life cycle, there is little wear and tear by cycling a supercapacitor. Unlike in a battery, age does not affect the device.
Supercapacitors today mostly use carbon due to its low cost, high surface area, high electrical conductivity and long-term stability. Scientists are working to improve energy density, power density and cycle stability of capacitors while trying to reduce production costs.