Scientists CONVERT YOUR HOME into one huge battery
Bricks could hold on to electrical charge if they were filled with special nanofibres, converting our homes into storage facilities for solar energy.
American scientists from Washington University in St. Louis have developed a brick that looks like a traditional red house brick, but which functions as a battery. The trick is to fill the brick’s pores with nanofibres made of a special plastic polymer that can maintain an electrical voltage. If our buildings could be converted into large batteries in this way, we could solve one of the biggest challenges of the switch to green energy, which is energy storage. Solar panels on your roof could generate electricity, with the bricks of your house storing the energy until you need it.
Technically speaking the new brick is not a battery, it is a super-capacitor. A capacitor consists of two current-carrying plates separated by a layer of some different material through which the voltage cannot travel. When you charge a capacitor, it is like rubbing a balloon against a sweater, generating negative and positive charges respectively, which attract each other. In a capacitor a negative charge is created on one of the plates and a positive charge on the other, producing an electrical field that polarises the layer between. The voltage difference remains in the layer until the energy is discharged as electricity to an external circuit.
A capacitor’s capacity increases when the surface of the plates is made larger, or when the distance between them is reduced. So a super-capacitor’s plates are lined with porous nanomaterials that provide them with a much larger surface area, while the plates are separated not by a thick layer, but via immersion in an electrolyte solution and separation by a thin plastic film. Both criteria are thereby satisfied – the same structure as that of an ordinary capacitor is obtained, but with a far larger surface area and lower distance between the plates.
The new Washington University electric brick functions like the plates of a supercapacitor. Scientists first deposit the currentcarrying plastic polymer PEDOT, which is covered in nanofibres, in the brick, after which they divide it in two and immerse the pieces into electrolyte gel. When the two brick halves are reunited, the scientists have a supercapacitor. The next stage will see the scientsts try to improve the capacitor’s energy density.