Imagine for a moment that a house, its own structure, was capable of storing energy. In other words, each of the bricks that make up its walls could act as a battery. That’s the surprising, though technically feasible, idea of a researcher at the University of Washington. Julio D’Arcy and his team had been working on the chemistry of rust, which gives the plains of Mars its reddish color. And the same goes for bricks used in construction down on Earth. Both share hematite or ferric oxide, the precursor mineral to iron. As such, hematite is conductive and can operate as an electrode. If you add the bricks’ porous microstructure, the possibilities begin to become more apparent.
Once the theory had been established, D’Arcy and his team permeated two vapors through the microstructure of a brick. When encountering the hematite ore, these generated a polymer called PEDOT. In this innovative technology project, a brick with 8% hematite was used, which became a material capable of storing and releasing energy thanks to the treatment. They were able to turn on an LED light for five minutes with three standard bricks.
These new bricks are not dense enough to store large amounts of energy, as it can be noticed. However, they do offer numerous advantages. For one thing, they are incredibly cheap to produce. Also, they can withstand multiple charging and discharging cycles without losing their properties. In D’Arcy’s experiment, the bricks were subjected to ten thousand cycles while maintaining 90% efficiency. And thirdly, they continue to function regardless of temperature or rain.
If we consider that a house usually incorporates hundreds of bricks, it would not be unreasonable to think that their energy storage capacities, especially from solar panels, offer a real benefit. In fact, the developer of these innovative batteries considers that fifty bricks would be enough to power the emergency lights for five hours. Indeed, such a solution will contribute to more sustainable construction.
Bricks are not the only common material candidate for the development of innovative batteries. Researchers at the University of California have explored the possibility of using sand as a component for a model that lasts three times longer than the current ones. One of the team members – remember, this is California – drew inspiration from the beach sand while out surfing. The result is a coin-sized battery that uses sand for its anode instead of conventional graphite. The first step of the process was to find a type of sand rich in quartz, also called silicon dioxide. It was then ground very finely, on a nanometer scale, and then purified to obtain the quartz. Finally, they mixed it with salt and magnesium and heated it. The salt retains the heat, while the magnesium has the quality of absorbing the oxygen, so that in the end, free of oxygen, the quartz became silicon.
The developers point out that the silicon obtained is in a porous state, which increases the usable surface area and multiplies conductivity. Who knows if this type of battery will improve the current lithium models’ durability, helping our cell phones and other devices to finally make it through the day.