A group of scientists from South
Korea have converted used-cigarette butts into a high-performing material that
could be integrated into computers, handheld devices, electrical vehicles and
wind turbines to store energy
Presenting their findings today, 5
August 2014, in IOP Publishing's journal Nanotechnology the researchers have demonstrated the material's
superior performance compared to commercially available carbon, graphene and
carbon nanotubes.
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It is hoped the material can be
used to coat the electrodes of supercapacitors—electrochemical components
that can store extremely large amounts of electrical energy—whilst also
offering a solution to the growing environmental problem caused by
used-cigarette filters.
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It is estimated that as many as
5.6 trillion used-cigarettes, or 766,571 metric tons, are deposited into the
environment worldwide every year.
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Co-author of the study Professor
Jongheop Yi, from Seoul National University, said: "Our study has shown
that used-cigarette filters can be transformed into a high-performing
carbon-based material using a simple one step process, which simultaneously
offers a green solution to meeting the energy demands of society.
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"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."
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Carbon is the most popular
material that supercapacitors are composed of, due to its low cost, high
surface area, high electrical conductivity and long term stability.
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Scientists around the world are
currently working towards improving the characteristics of
supercapacitors—such as energy density, power density and cycle
stability—whilst also trying to reduce production costs.
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In their study, the researchers
demonstrated that the cellulose acetate fibres that cigarette filters are
mostly composed of could be transformed into a carbon-based material using a
simple, one-step burning technique called pyrolysis.
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As a result of this burning
process, the resulting carbon-based material contained a number of tiny
pores, increasing its performance as a supercapacitive material.
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"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," continued Professor Yi.
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"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."
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Once fabricated, the carbon-based
material was attached to an electrode and tested in a three-electrode system
to see how well the material could adsorb electrolyte ions (charge) and then
release electrolyte ions (discharge).
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The material stored a higher
amount of electrical energy than commercially available carbon and also had a
higher amount of storage compared to graphene and carbon nanotubes, as
reported in previous studies.
Source: nanowerk ,IOPscience
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