Like harnessing the power of the sun or getting a charge from physical movement, the conversion of ambient energy into electricity is getting pretty old hat. Tapping multiple sources simultaneously, on the other hand, is something else altogether. The secret was under our noses this whole time. While minerals known as perovskites have shown promise for extracting one or two types of energy concurrently, one particular member of that family leaves them in the shade by distilling sunlight, heat, and movement into electricity at once.
Like all perovskites, KBNNO is ferroelectric in nature. This means it contains tiny electric dipoles, packed with positive charges on one end and negative charges on the other, according to scientists from University of Oulu, who described the material in the journal Applied Physics Letters this week.
Changes in temperature coaxes these dipoles to shift, which in turn induces an electric current. Likewise, mechanical stress causes parts of the material to attract or repel charges, producing another current.
KBNNO’s photovoltaic and ferroelectric properties have been the subject of prior research, but the Oulu study marks the first time anyone has evaluated properties relating to temperature and pressure. Previous studies also operated at temperatures hundreds of degrees below freezing, rather than above room temperature, as the latest experiments did.
Still, there was one wrinkle: Although KBNNO proved “reasonably good” at generating electricity from heat and pressure, scientists didn’t think it quite measured up to its fellow perovskites—at least, not without some tinkering, say by preparing KBNNO with sodium to amplify certain piezoelectric or pyroelectric properties.
“It is possible that all these properties can be tuned to a maximum point,” Yang Bai, who led the study, said in a statement.
By next year, Bai and his team say they hope to construct a prototype of a multi-energy-harvesting device, one that could render batteries for portable devices obsolete.
He said, “This will push the development of the Internet of Things and smart cities, where power-consuming sensors and devices can be energy sustainable”.