By: Romy de Weert
Researchers at the Massachusetts Institute of Technology (MIT) have discovered a new way to make a supercapacitor from cement, soot and water. It could form the basis for a new low-cost energy storage system under the house or in the road.

Supercapacitors made from this material have great potential to aid in the world's transition to renewable energy, says MIT professor Franz-Josef Ulm. Renewable energy, such as wind, solar and tidal power, all deliver at different times, which often do not match the peaks in electricity consumption. So ways to store that energy are essential.

“There is a huge need for large energy storage,” says Ulm. "Existing batteries are too expensive and mostly rely on materials such as lithium, whose supply is limited, so cheaper alternatives are desperately needed. That's where our technology is extremely promising, because cement is ubiquitous."

Super battery under your house
In MIT's new breakthrough, cement and carbon black are combined with water to make a supercapacitor. An alternative to batteries that can store electrical energy. The MIT researchers who developed the system say their supercapacitor could eventually be incorporated into a home's concrete foundation, where it could store an entire day's worth of energy. And that while it entails little or no extra costs.
How does a supercapacitor work?
A supercapacitor is a form of energy storage that can best be compared to a battery. It stores energy in the form of electricity. In the supercapacitor, this is done with two conductive plates that are immersed in an electrolyte. The advantage of a supercapacitor over a battery is that a capacitor can discharge relatively quickly. Moreover, the new supercapacitor can be made with common elements: cement, soot and water.


A 45 cubic meter piece of concrete could store about 10 kilowatt hours of energy. That is about as much as an average household consumes daily. A house with such a foundation could then store one day's worth of energy that is generated, for example, with solar panels.


Charging the car while driving
The researchers find another application for the concrete mixture in the construction of roads. The road, containing the supercapacitor, could store energy that is generated, for example, with solar panels or wind turbines along the road. The road with the supercapacitor in turn passes the energy to electric cars using the same kind of technology that is used to charge a phone wirelessly.
