Butt out of energy crisis

Jongheop Yi of Seoul National University and colleagues have demonstrated that the carbon-containing material of a used cigarette filter, the butt, can outperform other synthetic carbon materials, including graphene, as an energy storage medium with a single processing step. It is estimated that 5.6 trillion cigarette butts (about 766 571 tonnes) are deposited into the environment every year and while retrieving them might represent a significant logistical challenge, the potential for re-purposing this waste is high. “Our study has shown that used cigarette filters comprising cellulose acetate can be transformed into a high-performing carbon-based material using simple pyrolysis," says Yi. The process converts the butt into a porous supercapacitor material, which the team has tested in a three-electrode system. “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," adds Yi.