Researchers at the UC Berkeley and the U.S. Department of Energy’s Lawrence Berkeley Lab have developed a new lead-free material that generates electricity when exposed to stress. In one day this phenomenon called piezoelectricity could become as common as backyard grills.
Being a sustainable way to generate electric energy, piezoelectricity is a green alternative to burning fossil fuels because it works by applying stress or pressure on a certain crystalline materials, including certain ceramics and even bone. Until today, even the most popular piezoelectric materials have been composed of a notorious neurotoxin and lead. Thanks to this discovery, it could open the door to a piezoelectric energy future in which people generate huge amounts of electric energy.
By removing the lead hazard, the new discovery could prompt the use of piezoelectric materials not only in buildings and infrastructure, but also in common consumer products that are exposed to stress, such as T-shirts or shoes. The key to this amazing success is the use of bismuth ferrite, an inorganic crystalline material associated with magnetic-electric phenomena, generate a piezoelectric effect when subjected to large amounts of properly focused strain. Bismuth ferrite is composed of crystal planes that alternate between iron atoms and oxygen and bismuth atoms and oxygen ( bismuth being a heavy metal used in medicines and cosmetics).
“We have demonstrated that epitaxial strain can be used to create a large piezoelectric responses in thin films of bismuth ferrite,” says Ramamoorthy Ramesh, a materials scientist who led this research. “The piezoelectric effect is reversible when the strain is relaxed.”
“Inducing materials into such a schizophrenic state can be the key to obtaining exotic behavior.” said Ramesh.