Cigarette Butts Offer Solution To Supercapacitors’ Energy Storage

If you happen to notice a cigarette butt in a gutter, don't be too quick to scorn it as disgusting and useless.

Well, yes, it's still disgusting, but a team of South Korean scientists says it's no longer useless. In fact, they've used the butts to create a material that could store energy in superconductors for use in all manner of devices from computers to electric cars.

The stuff of cigarette filters, in fact, offers better performance than the substances already available for use in superconductors, such as carbon nanotubes and graphene, according to their findings published Aug. 5 in the Institute of Physics' journal Nanotechnology.

The key is energy storage in supercapacators, which store electrical charges, unlike batteries, which store energy in chemicals. Suprercapacitors are superior to batteries because they can load up on energy and discharge it much faster.

But batteries still have the edge on size. A supercapacitor to power a smart phone or a laptop would simply be too big to be practical for such a small form factor. So they're limited to industrial applications such as storing energy at wind farms, where size doesn't matter.

That's not good enough for most researchers, who are constantly looking for ways to improve supercapacitors.

Conventionally, the devices rely on carbon because it is inexpensive, has a high surface area, has strong electrical conductivity and is stable. Now the team from Seoul National University says it has found a way to transform the cellulose acetate fibers in cigarette filters into a carbon-based material in a single, simple step. The filters are burned using a technique called pyrolysis.

The resulting material contains many pores of different sizes, thus increasing its surface area and thus its performance. This is important in creating a high-performing supercapacitor, according to Professor Jongheop Yi, a co-author of the study.

"A combination of different pore sizes ensures that the material has high power densities, which is an essential property in a supercapacitor for the fast charging and discharging," Yi says.

The scientists attach this substance to one electrode in a three-electrode supercapacitor to learn how well it could absorb and release a charge. They found that their material stored more energy than conventional carbon, graphene and even carbon nanotubes. That means that their form factor can shrink.

Not only that, Yi says, but his team's findings "offers a green solution to meeting the energy demands of society. 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."

Only one question remains: Who's going to sweep up all those butts to maintain this new technology?

By Andy Tully of Oilprice.com