Researchers turn bricks into rechargeable batteries

You soon may be able to recharge your cellphone or laptop be plugging it into a wall. Not a wall outlet; the wall itself.

Washington University scientists have figured out how to transform a simple red brick into a power source for electronic devices.

The amount of energy the bricks can store is small now — not enough to power up a laptop. But researchers see a time when just a few bricks could store enough energy to feed an entire home.

"We have demonstrated an idea that no one had thought of — that materials that we use for building a house can have dual function," said chemistry professor Julio D'Arcy, who is leading the research. "That future can be a reality, and we can make it happen."

If successful, D'Arcy's bricks could provide a solution to one of the most vexing problems in the world of renewable power generation: How to store unused energy as it is being created so it can use it later.

Solar panels work well when it's sunny. But they can't be a sole energy source because most homes and offices aren't equipped to store energy for nighttime use. And, while storage technology exists, it is bulky and expensive.

If D'Arcy's plan works, bricks would become batteries, powering up homes and even entire communities.

"Every time I drive to work, I'm surrounded by bricks," he said. "When we started looking at nature for inspiration, it was staring me in the face every day."

A key to the breakthrough? Iron oxide, commonly known as rust — the pigment that gives a red brick its signature color. A regular brick contains about 6% iron oxide. D'Arcy figured that was enough to sustain a chemical reaction that would transform the inside of the brick.

He and his team put a brick into an oven heated to 320 degrees, and fill the oven with two gases: vaporized hydrochloric acid, to free up reactive ions of iron from rust, and a gas known as EDOT, which reacts with the iron ions. The product of that chemical reaction coats the brick's internal pores with a net of minuscule fibers that conduct electricity.

Others in the field say D'Arcy's work holds promise.

"I think the study is good and very creative," said Shoji Hall, assistant professor of materials science and engineering at Johns Hopkins University. "It never occurred to me that something like bricks could be used as templates to make energy storage materials," he added.