Supercapacitors (aka ultracapacitors or ultracaps) represent one of the most exciting technologies in the EV world today. Because of their superior charge/discharge rates and long cycle life, they could make great companions to lithium-ion batteries, which offer higher energy density. Some brave souls predict that they could someday replace batteries altogether in some applications.
Now a team of researchers at the Gwangju Institute of Science and Technology in Korea has used graphene to build a supercapacitor that can store almost as much energy as a lithium-ion battery (in August, a separate team in Australia announced its own compact graphene-based supercapacitor).
The Korean researchers produced a highly porous form of graphene with a huge internal surface area by reducing graphene oxide particles with hydrazine in water agitated with ultrasound. A single gram of the material has a surface area the size of a basketball court.
According to the team’s report, its supercapacitor has a specific capacitance of over 150 farads per gram, energy density of more than 64 watt-hours per kilogram, and current density of 5 amps per gram. It can be fully charged in 16 seconds and undergo 10,000 cycles without a significant reduction in capacitance.
Source: MIT Technology Review