Researchers at the University of Waterloo managed to significantly improve supercapacitors, by combining graphene with an oily liquid salt in the supercapacitors' electrodes.
The researchers explained that the liquid salt serves as a spacer to separate the thin graphene sheets, preventing them from stacking. That dramatically increases their exposed surface area, a key to maximizing energy-storage capacity. At the same time, the liquid salt doubles as the electrolyte needed to actually store electrical charge, minimizing the size and weight of the supercapacitor.
The innovation also uses a detergent to reduce the size of the droplets of oily salt - which is combined with water in an emulsion - to just a few billionths of a metre, improving their coating action. The detergent also functions like chemical Velcro to make the droplets stick to the graphene.
Increasing the storage capacity of supercapacitors means they can be made small and light enough to replace batteries for more applications, particularly those requiring quick-charge, quick-discharge capabilities. In the short term, better supercapacitors could displace lead-acid batteries in traditional vehicles, and be used to capture energy otherwise lost by buses and high-speed trains when they brake. In the future, if they ever manage to attain the full storage capacity of batteries, supercapacitors have the potential to conveniently and reliably power consumer electronic devices, electric vehicles and more.