Red bricks are among the cheapest building materials worldwide. Buildings made with them can be found everywhere. Now researchers from Washington University in St. Louis, Missouri, have turned them into energy storage units that can power electronic devices – thanks to the red pigment they contain and a conductive polymer coating called PEDOT. These new ‘smart bricks’ can be charged to hold electricity like a battery.
Up until now, the farthest people have gone in ‘thinking outside the brick box’ has been to utilize the materials thermal mass for heating and cooling by taking advantage of its ability to absorb and store the sun’s heat. Other than that, bricks have been used for thousands of years merely to enclose spaces and hold up roofs.
The team’s proof-of-concept demonstrates a brick directly powering an LED light. The breakthrough development could potentially transform buildings into giant supercapacitors. Imagine being able to use brick walls – which occupy vast amounts of space – for an additional purpose! Supercapacitors can store more energy and be charged more quickly than batteries. They can be stacked to save more energy, so the bigger the wall, the bigger the storage unit.
Dr. Julio D’Arcy, a Washington University assistant professor of chemistry, said:
Our method works with regular bricks or recycled bricks, and we can make our own bricks as well. As a matter of fact, the work that we have published in Nature Communications stems from bricks that we bought at Home Depot right here in Brentwood (Missouri). Each brick was 65 cents.
How a ‘smart brick’ is made:
- The scientists developed PEDOT – a coating made up of nanofibers that penetrate the porous structure of the bricks. It is what taps into the red pigments’ energy-storage potential and turns the block into “an ion sponge” that conducts and stores energy.
- Then they heated a set of bricks with acid vapor to dissolve the haematite (the mineral that gives off the red pigment) within.
- Once the haematite had dissolved, a few other compounds were added and then the PEDOT coating. The bricks changed color from red to a dark brownish-blue after the treatment and were riddled with a network of tiny, conductive PEDOT fibers.
- Lastly, they coated the treated bricks in epoxy to make them waterproof.
The final product could be connected to a power source to charge and store enough energy to power a light. Three bricks together kept a 3-volt green LED lit for about ten minutes on a single charge. It also worked underwater. After charging 10,000 times, the blocks lost no more than 10% of their storage capacity.
The team envisions the ‘smart bricks’ being hooked up to a renewable source of electricity, such as solar cells, to run lights and an array of microelectronic sensors.
Dr. D’Arcy said:
PEDOT-coated bricks are ideal building blocks that can provide power to emergency lighting. We envision that this could be a reality when you connect our bricks with solar cells – This could take 50 bricks in close proximity to the load. These 50 bricks would enable powering emergency lighting for five hours. Advantageously, if a brick wall serving as a supercapacitor can be recharged hundreds of thousands of times within an hour. If you connect a couple of bricks, microelectronics sensors would be easily powered.
[However], we don’t know whether the bricks maintain their strength when the haematite is dissolved. They were exposed to acid, so I would not use them for construction purposes, but we have not carried out mechanical testing. Instead, they could be used in a more decorative capacity.
The technology is still far from commercialization. Especially since, at the moment, it’s still costly. One brick costs about $2 to $3 to make. If the team can determine how to make ‘smart bricks’ cheaper, they could be an ideal building material as one brick would have more energy than an AA battery. Plus, we’d be able to plug our electronics right into the wall, which means less wiring necessary.
