Ultracapacitors are currently being used in applications that need high amounts of electricity in short times. Unlike conventional batteries, which can store much more energy but release it slower, ultracapacitors (or sometimes called supercapacitors) can survive for longer, because they don’t use the same chemical processes.
EnerG2, an Oregon-based startup, has recently received a $21.3 grant from the DOE to develop a special electrode made from activated carbon for increasing the ultracapacitors’ performance. EnerG2 says the materials could also be used in advanced batteries and suggests that its technology could be the key to “making gasoline obsolete.”
So far, most ultracapacitors have been made using organic materials, specifically coconut husk. One issue with the husks is that the impurities in it limit the ultracapacitors’ voltage. To deal with that, EnerG2 developed a synthetic material that can be adjusted to vary the ultracapacitors’ properties.
The company can increase the energy-storing capacity by changing the size and shape of the nanoscale pores, thus increasing the surface area and allowing the degree to which electricity can flow through the material. Additionally, the energy capacity can be increased to about 20 percent by allowing the ultracapacitor to work at higher voltages, and could cut the cost per watt-hour in half. “This is not one of those nanotechnologies that is too expensive to be commercializable,” says Rick Luebbe, CEO of EnerG2.
The company’s approach using activated carbon can drive other important changes in the energy storage industry. Not only ultracapacitors could benefit from activated carbon electrodes, but also batteries. It has been proven recently that well-ordered carbon electrodes, composed of regular rows of carbon nanostructures, are best for use in lithium-sulfur batteries, for example. These have a high current density, and the ordered carbon electrodes improve the overall conductivity and let the intrinsic chemical reactions perform better inside the battery.
Until batteries will feature such ordered activated carbon electrodes, because of their high production price, ultracapacitors carrying EnerG2’s innovation could be used in advanced battery systems to provide bursts of power and then recharge from the attached batteries.