MIT Scientists May Have Found a Cheap Way of Storing Huge Amounts of Energy in Cement

This "fascinating" material could power your entire house.

Cement Energy

A team of MIT researchers has figured out a way to create a supercapacitor simply by mixing cement, the binding ingredient of concrete, and a fine charcoal product called carbon black together with water.

Better yet, this mixture could allow a home to store a full day's worth of energy in its foundation, potentially paving the way to an efficient renewable energy storage solution that doesn't rely on mining rare Earth metals.

Roads made up of the material could even power electric cars wirelessly, the researchers say, or windmills could store their generated energy in their base.

"The material is fascinating," said co-author and MIT professor Admir Masic in a statement, "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."

Supercapacity

At least, that's the vision detailed in a new paper published in the journal PNAS.

Batteries and capacitors may perform the same function of storing energy, but they do so in fundamentally different ways. The former can distribute energy linearly through a chemical reaction, while capacitors release energy in bursts by storing energy as an electrostatic field.

Supercapacitors build on this ability by delivering energy at much faster rates than the average battery, which is also the source of their biggest drawback: the inability to release a charge slowly like a lithium-ion battery.

The researchers produced a cement-based material that has an extremely high internal surface area due to the many layers of conductive materials within.

Once soaked in a special salt solution, they say, the resulting material could act like a powerful supercapacitor.

"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," Masic said.

Unlimited Power

The mixture only requires as little as three percent of carbon per volume to achieve this complex network of carbon connections.

A block of about 1,600 cubic feet (45 cubic meters) in size could hold 10 kilowatt-hours of energy, roughly the average electricity usage of a household, the researchers found.

In experiments, the researchers started small, producing a 1-volt supercapacitor that's roughly the size of a button-cell battery, three of which could power LEDs.

The researchers are now experimenting with different mixes of the material to optimize how much energy can be stored and released.

While plenty of questions remain about its viability — if it can hold up in bad weather, for instance, or if it erodes over time — it's a fascinating new use of a material that's been around for thousands of years.

More on cement: They Turned a Brick Into a Battery