Angstron Materials Inc. (Dayton, Ohio) announced on Dec. 22 that it has invented a graphene-based supercapacitor with ultrahigh-energy density, a feature that permits storage of a significant amount of energy. As a rechargeable energy storage device, supercapacitors can be charged and discharged more quickly than batteries, but they have been challenged by their inability to store energy in the amounts required by automotive and electronic applications. Angstron’s graphene-based supercapacitor has demonstrated an energy density that exceeds that of commercially available supercapacitors and is comparable to nickel-metal-hydride batteries. Dr. Bor Jang, cofounder of Angstron, says, “This type of supercapacitor is especially attractive for electric vehicle applications where the pairing of supercapacitors with fuel cells or batteries could provide a hybrid system capable of delivering high-power acceleration and energy recovery during braking.” The company maintains that this development has pushed the specific energy density of an electrical double-layer (EDL) graphene-enabled supercapacitor to an unprecedented level of nearly 90 watt-hours/kg at room temperature and 136 watt-hours/kg at 80°C/176°F. Angstron’s single-layer graphene has exhibited the highest electrical properties, including exceptional in-plane electrical conductivity (up to ~20,000 S/cm), when compared to other nanomaterials, including carbon nanotubes (CNTs) and carbon nanofibers (CNFs).