Energy storage is a big deal in the modern world, as it is necessary for electronics to be mobile. Often we see batteries used for their high energy densities, but they have limited lifespans and can take a long time to charge. Supercapacitors are the reverse though, with almost unlimited lifespans and short recharging times, but low energy densities. Researchers at Monash University however have developed a new supercapacitor with energy densities comparable to lead-acid batteries.
All capacitors work by gathering opposite charges on separated electrodes, so an electric field forms between them, storing energy. Supercapacitors simply have the highest capacitance of all capacitors, and most are made of porous carbon with a liquid electrolyte to carry the charges. The researchers decided to build a new, compact electrode out of graphene, an atom-thick sheet of carbon with extraordinary electrical properties, by placing the liquid electrolyte in-between its layers, with sub-nanometer precision. This resulted in an energy density of roughly 60 Watt-hours per liter, compared to the more typical five or eight Watt-hours per liter of other supercapacitors.
Of course such a powerful supercapacitor would be of little use if it could not be mass-produced, and fortunately that should not be the case with this material. Manufacturing the electrode relied on a process similar to one used in paper making, so the transition from the laboratory to industry may not take too long.
Source: Monash University