Princeton and Caltech researchers have developed special silicone rubber sheets with embedded nanorods that, when bent, generate electricity with impressive efficiency. The technology is projected to be used as a power source for implantable devices like pacemakers by harnessing energy from moving organs like the thoracic cage.
The Princeton team is the first to successfully combine silicone and nanoribbons of lead zirconate titanate (PZT), a ceramic material that is piezoelectric, meaning it generates an electrical voltage when pressure is applied to it. Of all piezoelectric materials, PZT is the most efficient, able to convert 80 percent of the mechanical energy applied to it into electrical energy.
Fabrication starts with the researchers producing PZT nanoribbons — strips so narrow that 100 fit side-by-side in a space of a millimeter. In a separate process, they embedded these ribbons into clear sheets of silicone rubber, creating what they call "piezo-rubber chips." Silicone, which is used for cosmetic implants and medical devices, already is biocompatible. "The new electricity-harvesting devices could be implanted in the body to perpetually power medical devices, and the body wouldn’t reject them," McAlpine said.
In addition to generating electricity when it is flexed, the opposite is true: The material flexes when electrical current is applied to it. This opens the door to other kinds of applications, such as use for microsurgical devices, McAlpine said.
Full story from Princeton: Energy-harvesting rubber sheets could power pacemakers, mobile phones…
Abstract in Nano Letters: Piezoelectric Ribbons Printed onto Rubber for Flexible Energy Conversion