MIT experts are studying whether houses and roads can become unlimited sources of energy

The scale and pace of the transition from fossil fuel to one based Renewable energy will largely depend on the availability of solutions storage volumetric energy to effectively manage the imbalance between supply and demand.

Within this framework, researchers Massachusetts Institute of Technology (MIT) developed a new way store electricity in cement, using cheap and available materials. On an enlarged scale, cement can hold enough energy in a house’s concrete foundation to meet your daily energy needs. Expanded further, electrified roads can increase electric vehicles while they drive. And if scientists can find a way to do all this cheaply, the breakthrough could be a real breakthrough. almost unlimited power for energy storage from intermittent renewable sources such as solar and wind.

As long as the cement fixtures are small, big enough to power multiple LED bulbs. But efforts to expand them are already being made. These new items some kind of simplified battery call supercapacitors. They consist of two electrically conductive plates separated by an ion-conducting electrolyte and a thin membrane. As the mechanism charges, positively charged ions from the electrolyte accumulate on one plate, and negatively charged ions on the other.

The amount of stored energy depends on the total surface area of ​​the conductive plates supercapacitor. For decades, researchers have tried to incorporate them into structural materials such as concrete used in roads and buildings, or carbon composites used in car and aircraft bodies. Unlike the best modern batteries, supercapacitors usually use non-flammable electrolyteswhat makes them safer.

The problem MIT faced when they started their work was that cement, main component of concrete, usually a bad electrical conductor. So, in recent years, several groups have made structural supercapacitors by adding shapes carbon has a high conductivity in relation to cement, How graphene or Carbon nanotubes.

Although they work well ingredients are expensive and difficult to produce in the huge volumes used in the cement industry,” said Franz-Josef Ulm, a civil engineer at the Massachusetts Institute of Technology (MIT) and one of the paper’s lead authors.

In search of a cheaper alternative, Ulm and his colleagues turned to the old way coal powder known as jet black, which has been used since ancient times as black pigment. cheap and lots all over the world it is also highly conductive. Ulm and his team mixed a small percentage of this substance with cement powder and added water, which mixes easily with cement. But because the soot particles repel it, they tend to stick together, forming long interconnected tendrils inside the hardened cement that act like a web of cables.

Specialists cut this wire cement into small plates, creating supercapacitors 1 millimeter thick and 1 centimeter wide, the size of a button. After adding the membrane, the electrolyte from potassium chloride, simple salt and water, the researchers sealed the structure of this kind of sandwich. When they connected the wire to the plates and flipped the switch, cement supercapacitors lit a lot of LED lamps.

If carbon black cement were used to make 45 cubic meters of concrete, that’s about the same amount used for the foundation of an apartment building. A standard house, it can store 10 kilowatt-hours of energy, which is enough to power an average house for one day. If the same approach were used to build ways and ways parking lots or driveways, electrified concrete can store renewable energy and deliver it to electric vehicles using inductive chargers.

One approach might be to supply electricity to the underside of the car through copper coils built into the road, something like how wireless systems charge smartphones. This technology is already being developed in Germany and in Netherlands.

“Offering cheaper alternative to more expensive batteries, electrified cement can also make Energy storage renewable energy sources are more accessible to developing countries,” said Admir Masic, a chemist at the Massachusetts Institute of Technology and co-author of the study. This puts us in a new space to store energy at affordable prices anywhere in the world.”

To be successful, the researchers will need to enlarge the plates to the size of a button. “It’s not trivial,” Nguyen said. How do supercapacitors become more, their electrical conductivity usually decreases, which makes it difficult to input and extract energy from them. One solution is to simply add more carbon black to the mixture, but not so much that it weakens the structural integrity of the cement.”

Researchers have found that for structural concrete, they can add up to 10% carbon black without compromising its strength too much. Ulm says that “the group patented his technology and now he is working to increase the power to the level of a 12-volt car battery.”

The investigation was completed with the participation of experts Nicolas Chanut, Damian Stefaniuk and James S. Weaver.

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