Chalcogenide perovskite film generates electricity when squeezed or stressed

Imagine tires that charge a vehicle as it rolls, streetlights powered by the roar of traffic, or skyscrapers that generate electricity as buildings naturally sway and shudder.

These energy innovations could be possible thanks to researchers at Rensselaer Polytechnic Institute who are developing environmentally friendly materials that produce electricity when compressed or exposed to vibration.

In a recent study published in the journal Natural communicationsThe team developed a polymer film infused with a special chalcogenide perovskite compound that produces electricity when squeezed or stressed, a phenomenon known as the piezoelectric effect.

Although other piezoelectric materials currently exist, this is one of the few high-performance materials that does not contain lead, making it an excellent candidate for use in machinery, infrastructure as well as in biomedical applications.

“We are excited and encouraged by our findings and their potential to support the transition to green energy,” said Nikhil Koratkar, Ph.D., corresponding author of the study and the John A. Clark and Edward T. Crossan Professor at the department. of mechanical, aerospace and nuclear engineering.

“Lead is toxic and is increasingly restricted and eliminated from materials and devices. Our goal was to create a material that is lead-free and can be manufactured inexpensively from elements commonly found in nature .”

The energy harvesting film, which is only 0.3 millimeters thick, could be integrated into a wide variety of devices, machines and structures, Koratkar explained.

“Essentially, the material converts mechanical energy into electrical energy: the greater the pressure load applied and the larger the surface area over which the pressure is applied, the greater the effect,” Koratkar said. “For example, it could be used under highways to generate electricity when cars drive over them. It could also be used in construction materials, producing electricity when buildings vibrate.”

The piezoelectric effect occurs in materials that lack structural symmetry. Under stress, piezoelectric materials deform in such a way that the positive and negative ions contained in the material separate. This “dipolar moment,” as it is scientifically called, can be harnessed and transformed into electric current.

In the chalcogenide perovskite material discovered by the RPI team, the structural symmetry can be easily broken under stress, leading to a pronounced piezoelectric response.

Once their new material, which contains barium, zirconium and sulfur, was synthesized, the researchers tested its ability to produce electricity by subjecting it to various body movements, such as walking, running, clapping and tapping fingers.

The researchers found that the material generated electricity during these experiments, enough to power even banks of LEDs labeled RPI.

“These tests show that this technology could be useful, for example, in a device worn by runners or bikers that lights up their shoes or helmets and makes them more visible. However, this is only evidence of concept, because we hope we will eventually see this type of material implemented on a large scale, where it can actually make a difference in energy production,” Koratkar said.

In the future, Koratkar’s lab will explore the entire family of perovskite chalcogenide compounds in search of those that exhibit an even stronger piezoelectric effect. Artificial intelligence and machine learning could prove useful tools in this quest, Koratkar said.

“Sustainable energy production is vital to our future,” said Shekhar Garde, Ph.D., dean of the RPI School of Engineering. “Professor Koratkar’s work is a great example of how innovative approaches to materials discovery can help solve a global problem.”