Rubber sheets could power cellphones and pacemakers

Posted by Emma Woollacott

A new power-generating rubber material could use natural body movements such as breathing and walking to power pacemakers, mobile phones and other electronic devices.

The material, made of ceramic nanoribbons embedded onto silicone rubber sheets, generates electricity when flexed and is highly efficient at converting mechanical energy to electrical energy.

Shoes made with it could power mobile electrical devices, while sheets of it next to the lungs could power pacemakers, making surgical replacement of their batteries unnecessary.

The Princeton University team combined silicone and nanoribbons of lead zirconate titanate (PZT). Of all piezoelectric materials, PZT is the most efficient, able to convert 80 percent of the mechanical energy applied to it into electrical energy.

"PZT is 100 times more efficient than quartz, another piezoelectric material," said Michael McAlpine, an assistant professor of mechanical and aerospace engineering at Princeton, who led the project. "You don't generate that much power from walking or breathing, so you want to harness it as efficiently as possible."

As well as generating electricity when it's 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.

"The beauty of this is that it's scalable," said Yi Qi, a postdoctoral researcher at Princeton. "As we get better at making these chips, we'll be able to make larger and larger sheets of them that will harvest more energy."