Storing energy in red bricks

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New research from Washington University in St Louis has found that ordinary red bricks can be converted into energy storage units that can be charged to hold electricity, like a battery.

Chemists have developed a method to make or modify "smart bricks" that can store energy until required for powering devices. A proof-of-concept published Aug. 11 in Nature Communications showed a brick directly powering a green LED light.

"Our method works with regular brick or recycled bricks, and we can make our own bricks as well," said Julio D'Arcy, assistant professor of chemistry.

Walls and buildings made of bricks already occupy large amounts of space, which could be better utilized if given an additional purpose for electrical storage. While some architects and designers have recognised the brick's ability to absorb and store the sun's heat, this is the first time anyone has tried using bricks as anything more than thermal mass for heating and cooling.

The research team has shown how to convert red bricks into a type of energy storage device - a supercapacitor.

"We have developed a coating of the conducting polymer PEDOT, which is comprised of nanofibers that penetrate the inner porous network of a brick; a polymer coating remains trapped in a brick and serves as an ion sponge that stores and conducts electricity," D'Arcy explained.

The red pigment in bricks -- iron oxide, or rust -- is essential for triggering the polymerisation reaction. The team's calculations suggest that walls made of these energy-storing bricks could store a substantial amount of energy.

"PEDOT-coated bricks are ideal building blocks that can provide power to emergency lighting," D'Arcy said. "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, 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."