MIT engineers created a carbon-cement supercapacitor that can store large amounts of energy. Made of just cement, water, and carbon black, the device could form the basis for inexpensive systems that store intermittently renewable energy, such as solar or wind energy.

People at MIT made a capacitor of cement and carbon black (not to be confused with soot). It worked and they are planning to test bigger samples. The construction of such capacitors is easy and they can be structural elements in architecture.