Two different lines of research in Korea and Australia seem to be heading toward practical supercapacitors with energy densities approaching the lower end of battery technology while offering better charging efficiency and extended lifetimes. Santhakumar Kannappan, a researcher at the Gwangju Institute of Science and Technology in Korea has led a team who reduced graphene oxide particles with hydrazine in water, then agitated the slurry with ultrasound. This produces a “highly porous form of graphene that has a huge internal surface area,” equivalent to a basketball court for every gram. They pack the resulting powder into a coin-shaped cell, dry it at 140° C and a pressure of 300 kilograms per centimeter (4,267 pounds per square inch) for five hours. Electrodes made this way and saturated in EBIMF 1 M electrolyte have a specific capacitance of 150 Farads per gram, an energy density of 64 Watt-hours per kilogram and a current density of 5 Amps per gram. MIT’s Technology Review …