New Nanoscale supercapacitor can store 100 times more energy
"March 23, 2009 It has been a big week for news on advances in energy storage technology. We recently reported on new research that makes a Lithium Ion battery perform more like a supercapacitor, now we can report on research on a supercapacitor that performs more like a battery. Researchers at the University of Maryland and the Korea Advanced Institute of Science and Technology have developed a supercapacitor with 10 billion nanoscale capacitors per square centimeter, giving it 250 times greater surface area than that of a conventional capacitor of comparable size. The Nano Supercapacitor is being developed primarily as part of a hybrid battery-capacitor system for electric cars.
Batteries, particularly lithium-ion, store large amounts of energy but have more difficulty with high power or fast recharge. Capacitors, on the other hand, can be charged or discharged at a very high rate. Existing supercapacitors have an energy densities around 1/10th that of a conventional battery, but their power density is generally ten to one-hundred times as great
The Maryland/KAIST research team’s new devices are electrostatic nanocapacitors which increase the energy storage density of such devices by a factor of 100 over that of commercially available devices without sacrificing the high power they traditionally characteristically offer. Current commercial supercapacitors range from 0.5 to 30 wh/kg, while the research is in its early stages, if they reach their claim of a 100 increase that will result in 3000 wh/kg. For comparison, a conventional lead-acid battery is typically 30 to 40 wh/kg and modern lithium-ion batteries are about 160 wh/kg. In automobile applications gasoline contains around 12,000 wh/kg, which operates at 15% tank-to-wheel efficiency giving an effective energy density of 1800 wh/kg"