Chemistry, Materials & Packaging
Why Dirty Cigarette Butts Could Become a Clean Energy Storage Solution

A team of South Korean scientists has converted cigarette butts into a valuable material that they say could be used as an energy storage device in computers, electrical vehicles, wind turbines and various handheld devices.

As reported by the Institute of Physics (IOP), and published in their journal Nanotechnology, the researchers demonstrated that the material proved superior to commercially used alternatives such as carbon, graphene and carbon nanotubes. The breakthrough could represent a win-win — acting as an electrical storage device while providing a solution to the increasing environmental burden caused by used cigarette filters.

Using a one-step burning process called pyrolysis (essentially, burning in low-oxygen conditions — the process used to generate biochar), the scientists showed that the cellulose acetate fibers within cigarettes filters could be converted into a carbon-based material comprised of a number of tiny pores (increasing its surface area), increasing its potential as a supercapacitive material.

The expectation is that the high-performing material could be used to coat the electrodes of supercapacitors (components used in electrical devices for their ability to store large amounts of energy). Carbon has predominantly been the preferred material until now, offering many benefits including its high surface area and electrical conductivity, long-term stability and low cost to produce.

Like most of the disposable materials we now use, the waste issue surrounding cigarette butts — which are toxic and non-biodegradable in the natural environment — is continuing to grow. It’s estimated that as many as 5.6 trillion butts (which equates to 766,571 metric tons) are disposed of as waste every year.

Speaking to the Institute of Physics, 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.

“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.”

With the increasing production of electrical devices and growing demand for energy storage, improving the characteristics of supercapacitors (including energy storage, power density and cycle stability) has been a goal for scientists across the globe. Reducing the cost of production has also been a target for wider distribution.

“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. 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 said.

To test its performance, the carbon-based material was attached to an electrode in a three-electrode system to see how well it could adsorb and then release electrolyte ions (essentially charging, then discharging, like an energy storage device) — the butt material performed better than all commercially available materials.

As the pursuit of technological developments (such as electrical vehicles [EVs]) to wean ourselves from fossil fuels becomes ever more pressing, the hunt for high-performing energy storage devices continues. In May, Japanese startup Power Japan Plus released a new carbon-based battery that was reported to generate twice as much energy as the conventional lithium ion battery, and charge twenty times faster. Although most EVs on the market are powered by lithium batteries (with Ford and Samsung announcing their development of a dual battery system in June), the Japanese company suggested that its carbon-based material could lead to cheaper long-range EVs that can travel hundreds of miles, after charging for minutes rather than hours.

Last month, ScienceDaily reported that the advantages of graphene supercapacitors (such as their faster charging times) over conventional EV batteries could play a key role in increasing their market appeal in countries such as Germany, where public interest is relatively low — partly due to long charging times. Perhaps the newfound cigarette butt solution could do this one better.