Storing Energy in Cement

New tech turns homes or roads into power reserves

The issue with non-fossil fuel energy is, it could be argued, storage. Take solar. When the sun is shining, sunlight converts into energy. Homes and businesses can use the energy. But, it’s a little inefficient. At night, during cloudier days, when too many people need power? Then energy directly through sunlight may not be in enough abundance.

What society needs is good storage. Good energy storage.

Thanks to some smart people at MIT, we may be on the cusp of good energy storage! A new innovation that employs readily available materials like cement, water, and carbon black to offer up an exciting paradigm of having energy at hand, in the form of capacitors.

By incorporating these common materials into supercapacitors, researchers have unlocked the potential to store and release energy efficiently, paving the way for a more stable and sustainable energy grid. These are elements that could be present in the foundation of a home, in the composition of a local road. Think of that! Roads that not only take you to and fro, but also have the ability to recharge your electric vehicle.

The researchers are not stopping there. They envision scaling up this technology to integrate such supercapacitors into wind turbine bases, further enhancing the efficiency of renewable energy generation. The future holds the promise of roads woven with this energy-storing technology, seamlessly charging electric vehicles as they travel, creating a cleaner and more sustainable transportation network.

The key to the technology is the mixing of carbon black — which is highly conductive — into a concrete mixture along with cement powder and water, and letting it cure. The water and carbon react to the cement by forming a branching network of openings. These structures have a fractal-like structure very, very thin. This thin structure with large surface area and small overall volume acts as the electrodes in the capacitor. Like:

Voila! A very powerful super capacitor. When connected to a source of electricity, energy gets stored in the plates, and then when connected to a load, the electrical current flows back out to provide power.

“The material is fascinating, because you have the most-used manmade material in the world, cement, that is combined with carbon black, that is a well-known historical material — the Dead Sea Scrolls were written with it. You have these at least two-millennia-old materials that when you combine them in a specific manner you come up with a conductive nanocomposite, and that’s when things get really interesting.”

Admir Masic MIT professor and co-author of a recent JNAS paper

Initial theorized uses for this type of capacitors would be with rural homes far from existing power grids. This application would see solar panels attached to the cement super-capacitors. 

Further down the road (pun!) the authors see a vehicle-charging highways, offering concrete layers that store energy produced alongside the roadways and employ wireless recharging to battery powered vehicles traveling along.