Several MIT researchers have come up with a way to store large amounts of energy in very different materials those commonly used in batteries. As for example, in cementwhich may lead to the development of alternatives to conventional batteries from basic materials.
As a result of the investigations, at MIT they assure that cement blocks into which a form of carbon very similar in appearance to soot is injected could store enough energy to supply electricity to homes. A block of about 3.5 meters, for example, could store up to 10 kW per hour of energy, and supply energy to a house for a whole day.
Far from being something utopian and hypothetical, the researchers who have come up with this system assure that the technology that makes it possible to transform basic materials into energy stores can be put on sale in a few years.
In addition, the discoverers of this advance, which among others are the MIT professors Franz-Josef Ulm, Admir Masic, and Yang-Shao Horn; They ensure that with the integration of similar batteries on roads they could get the cars that circulate on them to charge their batteries. This would be achieved by installing solar panels on the sides of the roads, which would generate the energy that would pass to the road with the capacitors, and from it to the cars. This is how they have collected it in an article about their discovery already published.
The MIT researchers discovered that carbon black, a form of this element found in partly burned materials, can be added to cinder blocks as they are being formed, turning them into supercapacitors. Thanks to this, they are capable of storing large electrical charges.
Capacitors store electrical charge in separate metallic conductors. The amount of energy they store depends on the surface area of the conductive material, and what the researchers have found is that they could create a large surface area very easily. Just adding carbon black to wet cement.
Carbon black is very conductive, and it diffuses into wet cement, getting into the voids left by water as it reacts during the curing process. This generates a network of small, cable-like microfibers within a solid cement block, structured in a fractal fashion, and with several branches leading to smaller ones.
Once the mixture is made and the block is created, it is submerged in salt. For example, in potassium chloride, which acts as an electrolyte and provides the charged particles that accumulate in carbon structures. Two electrodes created with this material, and separated by a small gap, or by an insulating layer, become a very powerful supercapacitor. These cement capacitors can be made anywhere in the world, and the blocks work with only 3% carbon black in the mix used to create them.
These blocks could be of great help in the energy transition, because more and more energy storage capacity is needed around the world to balance energy production with renewable sources. This happens with solar and wind energy, which are not consumed at the same time they are produced, which makes their storage necessary.
Existing batteries are expensive, and rely on uncommon materials, such as lithium. Therefore, its supply is limited, and the difficulties that this generates could end with this type of capacitors, created with materials that are available anywhere. Also, in the case of data centers, it may be possible with this technique to have energy storage batteries that are part of the building structure.
Should more powerful capacitors be required, they can be made using a higher concentration of carbon black, albeit at the expense of sacrificing some of the structural strength of each cinder block, so they would have to be created and used with care. . They could be useful in situations where the cement does not play a structural role, or where the full potential strength of the cement does not need to be used.
When they are used in the construction of foundations, or in the development of structural elements of the base of a wind turbine, for example, the optimum percentage of presence of carbon black in the mixture is around 10%, according to the team of researchers. who made the discovery.
The team, which began to develop this system by creating supercapacitors so small that they were no more than the size of a button, now plans to make blocks the size of a 12-volt car battery. Once this is achieved, they want to work on a 45 cubic meter version, with the aim of demonstrating its ability to store the energy necessary for a building.
