Turning red bricks into energy
The brick walls of your house or garden could one day charge your computer or television.
Researchers at Washington University in St Louis have developed a method of converting red bricks into battery-like devices known as supercapacitors.
A brick supercapacitor powering an LED light. Picture credit: The D’Arcy Laboratory at Washington University in St. Louis.
“Bricks have been around for thousands of years but we’ve added value and new functionality to them,” says Julio D’Arcy, a chemist at the university.
His team developed a proof-of-concept device which was able to power a green LED light. The “smart-bricks” are coated with a conducting polymer called PEDOT.
This polymer is made up of nanofibres that penetrate the inner porous network of the brick. The polymer coating remains trapped inside the brick, serving as an ion sponge that stores and conducts electricity.
A Brick Before and After Coating. These photos and microscope images show the structure of a common fired red brick before and after deposition of the nanofibrillar coating. Researchers cut a section from a brick using a diamond saw then used a light microscope to examine its red microstructure and then used a scanning electron microscope to examine its rough nanoscale architecture. They applied the same microscopy techniques to a polymer-coated brick. The brick is now blue coloured, and its surface is coated by strands of nanofibres of the conducting polymer PEDOT. Picture credit: The D’Arcy Laboratory at Washington University in St. Louis.
A key element is the red pigment in the brick, which is iron oxide or rust. Rust is essential for triggering the reaction. D’Arcy’s team say walls of “smart-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.
A cartoon of a house built using PEDOT bricks demonstrating future applications where devices are readily charged from the wall and the wall is readily recharged from a solar cell panel. Picture credit: The D’Arcy Laboratory at Washington University in St. Louis.
"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."
Any brick - regular, recycled or specially made - can be used. But there’s no indication of when or if the research will be commercialised.