Scientists Have Turned Bricks Into Batteries

These bricks could power a house someday.
These bricks could power a house someday.
Photo: Dibyangshu Sarkark/AFP (Getty Images)

We build homes out of bricks for lots of reasons. They’re resilient to high pressure and frost. They can withstand fluctuating temperatures without shrinking, expanding, or warping. They’re great at absorbing heat. They’re durable and can be reused. And according to a new study in Nature Communications, they can also be developed to store energy.

Advertisement

Bricks gets their warm, brownish-red hue from hematite, an iron oxide commonly found in rocks and soil that humans have been using as a pigment for 73,000 years. Interestingly, hematite is also used at state-of-the-art energy storage facilities. With that in mind, the chemists who authored the study developed a method to modify bricks to allow them to store electricity that can be used to power devices.

The authors bought some bricks from their local Home Depot and coated them with a gas made of a particular molecule. Since bricks are porous, that gas got into every nook and cranny of the bricks. When that molecule interacted with the hematite in the bricks, it triggered a polymerization reaction, creating a polymer known as PEDOT, which can store and conduct electricity. They knew the chemical process worked because when they put the bricks in the oven, they came out not red, but blue.

Using a solar cell, the chemists then gave half the bricks a positive charge and half of them a negative charge and connecting them with copper tape. This essentially turned the bricks into a battery, ready to store energy that can power a device when a switch is flipped.

As proof of concept, they tried this out on some of their bricks and got them to power a small LED light. Check it out:

Illustration for article titled Scientists Have Turned Bricks Into Batteries
Image: Julio Darcy
Advertisement

These brick batteries can be recharged in about 13 minutes, and have a lifetime of about 10,000 charges. This is all very exciting, but right now, the bricks can’t store a ton of energy.

Julio D’Arcy, assistant professor of chemistry at Washington University in St. Louis, who worked on the study and runs the lab where it was conducted, said 50 bricks can store enough electricity to power three watts of emergency lighting for 50 minutes but that “the amount of intensity of light is going to decrease over that time.” Three watts is roughly equivalent to an LED desk lamp.

Advertisement

“We could just increase the number of bricks to increase the amount of energy you can stored, but we know that’s not a great strategy because coating more and more bricks can get expensive,” D’Arcy said.

The brick batteries could also be used to power small electronics such as carbon dioxide detectors which don’t require much energy, but the chemists are thinking bigger. D’Arcy said if the team manages to increase the amount of energy the bricks can store by an order of magnitude, they’d be on par with the storage capability of a lithium battery. Eventually, the chemists hope the bricks can be integrated into solar-powered homes to allow them to store energy, which could be particularly useful during storms or other events that threaten power supply.

Advertisement

And since they’re made with PEDOT, D’arcy said, the bricks could have a lot of potential in the building industry. In addition to energy storage, other researchers are developing ways to use bricks to purify water. So one day, it’s possible your house’s walls could provide the electricity you use and the water you drink.

There’s a long way to go until these bricks are ready to be used for homes. But if chemists successfully improve their power, D’Arcy said it’s not hard to imagine their widespread use, because we’re so used to using bricks. We’ve already been using them for tens of thousands of years.

Advertisement

“Bricks are so special to humans. We live in them, we’re always interacting with them,” he said. “We just want to improve them.”

Earther staff writer. Blogs about energy, animals, why we shouldn't trust the private sector to solve the climate crisis, etc. Has an essay in the 2021 book The World We Need.

DISCUSSION

dnapl
Dense non aqueous phase liquid

To make a good brick, such as the highly coveted Chicago Common, you need a lot of energy (heat). That energy was from coal and manufactured gas (coal gas). It’s now typically natural gas. So researchers should do an energy balance.

Speaking of Chicago, clay and brick, Elon Musk’s The Boring Company was looking into doing something with clay spoils from tunneling between Chicago’s Loop and O’Hare. That’s the famous Chicago Blue Clay. There could be a marketing tie-in between the researchers at Wash U and Musk.

(BTW, Chicago became the world’s brick manufacturing capital after the 1871 fire required use of brick for building.)

Wash U researchers could review this USGS report written in 1903 to help with sourcing of good brick, since typically the clay source for brick manufacturing is fairly local. Brick properties vary widely.

The Clays of the United States East of the Mississippi River

Wrong side of the Mississippi, as far as researchers location, though. From the wonderful report on common brick:

(bolding done by me)

A clay to be used for the manufacture of common brick should burn red if possible, since there is then more possibility of its burning dense at a comparatively low temperature and thus avoiding the use of too much fuel. Most brick clays are burned to about cone 0.05, and at this temperature the clay commonly shows incipient fusion. Good brick clays should burn hard at a temperature of not over 2,000° F., namely, at cone 1, or preferably lower. This means the presence of sufficient fluxing material to bind the clay grains together into a hard body when burned. Large sand grains and pebbles are undesirable, for they tend to make the product porous and weak. The best results are commonly obtained with clays carrying from 5 to 7 per cent of ferric oxide. The residual limestone clays are often ferruginous, and those derived from gabbros or other dark-colored igneous rocks of the crystalline area are often highly so-too much so, in fact, for the production of really good brick. 

Screenshot showing brick properties from the 1903 USGS report:

Notice ferric oxide ranges from 0.126% to 15% depending on clay source.