Scientists Turn Cigarette Butts Into Electrical Storage
By burning them. No, really.
The electrical power of the future just might be waiting in ashtrays across the world. Researchers in South Korea discovered that, with a one-step conversion process, cigarette filters turn into great supercapacitors.
Supercapacitors are an electrical storage alternative to batteries. In batteries, energy is stored in chemical reactants, while in supercapacitors, it's stored as an electrical field between materials. Batteries are slow to charge and heavy, but they're also compact and store great amounts of energy, which means they've long held an advantage in consumer products. But supercapacitors work where space constraints matter less: Braking in a car generates a lot of electricity, and in some cars supercapacitors capture that energy and then release it to get the car going again. Unlike batteries, supercapacitors can release bursts of power more quickly, making them useful in electronics like defibrillators. Think of it like static electricity from wearing wool socks on carpet - the charge builds up quickly and is then released all at once in a spark.
Well it turns out that the collections of fibers in cigarette filters have a lot to offer a supercapacitor. Here's how the scientists described the process:
Used cigarette filters are composed largely of cellulose acetate. They are disposable, non-biodegradable, toxic and are a threat to the environment after usage. However, it has been reported that cellulose acetate can be directly utilized in the production of carbon materials containing a meso-/micropore structure by only a carbonization process . That is, used cigarette filters could be used as a proper carbon source for supercapacitors. Importantly, carbonizing used cigarette filters in a nitrogen-containing atmosphere could provide the nitrogen doping on the carbon structure with the formation of such unique pore structures in a one-step process.
In essence, the scientists burned the filters in a nitrogen-rich environment, and this made the filter fibers grow pores, further increasing their surface area. According to their results, published in the journal Nanotechnology, these burnt-in-nitrogen fibers stored more energy than materials previously used in supercapacitors. With further research, this could be great news for both electrical storage and ashtrays everywhere.
Cigarette butts transformed into high-performance supercapacitor component
Scientists from Seoul National University found that through a process called pyrolysis, the cellulose acetate fibers that make up the filter of a cigarette could be transformed into a carbon-based material that can be used as a high-performing component for supercapacitors; long-lasting, fast-charging devices capable of storing huge amounts of energy. The pyrolysis process involves a one-step burning technique that creates tiny holes of varying size in the material to increase its total surface area.
“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 Jongheop Yi, one of the study's authors. “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."
The team put its new material to the test by attaching it to an electrode and observed it in a three-electrode system, taking note of the material's ability to absorb and then discharge electrolyte ions. They found it stored a higher amount of electrical energy than graphene, carbon nanotubes and carbon, a material popular for use in conventional supercapacitors.
The scientists are hopeful that by coating the supercapacitor's electrode in the new carbon-based material, it could lead to better energy storage for electric vehicles, wind turbines and mobile devices.