What is the fine-grained topic of the following text: (Nanowerk News) Reporting their findings in the IOP Publishing journal Nanotechnology ("Preparation of energy storage material derived from a used cigarette filter for a supercapacitor electrode"), the research team successfully converted used cigarette butts into a high performing material that could be integrated into computers, handheld devices, electric vehicles and wind turbines to store energy. Only return the topic.
Conversion of used cigarette butts into energy storage material for electronic devices and turbines