Researchers want to use cement in foundations as a battery material
Researchers have found a way to make a supercapacitor from cement. This would make it possible to store electricity here and, in theory, relatively cheap batteries could be made from house foundations and roads.
The research, conducted by the Massachusetts Institute of Technology, has been published in the scientific journal PNAS. In addition to cement powder, water and black carbon were used to create the supercapacitor. Cement itself is not a very good conductor, but black carbon is. Moreover, the latter material is relatively cheap.
When these materials are combined in a specific way, a conductive nanocomposite is created. This is because the water combines easily with the cement powder, but the black carbon particles actually repel water and then clump together. This creates ‘vine-like’ shapes in the hardening cement that can act as a network of wires. The cement is then cut into thin slabs. If a membrane and electrolyte are then added, for example potassium chloride, the capacitor must be able to store and release energy.
This requires a lot of cement. 10kWh, enough to power an average household for a day, is expected to require 45 cubic meters. That is approximately the same amount as is used for the foundation of a standard house. The cement capacitors the researchers created, measuring 1mm thick and 1cm wide, had enough power to light a few LED lights.
The research team believes that if the same method is used to build roads and parking lots, the electric concrete could theoretically store renewable energy and supply it to electric cars via inductive charging. Because the materials are relatively cheap compared to other home batteries, this is also a possible way for third world countries to store green energy.
The group has patented the technology and is now trying to scale it up. That is not an easy job, says the team. As supercapacitors increase in size, their electrical conductivity generally decreases. The next goal is to make the cement capacitor as powerful as a 12V car battery.