Rubber films harness body movements

The material, composed 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 of the material may one day harvest the pounding of walking and running to power mobile electrical devices. Placed against the lungs, sheets of the material could use breathing motions to power pacemakers, obviating the current need for surgical replacement of the batteries that power the devices.

The Princeton team claims to be the first to successfully combine silicone and nanoribbons of lead zirconate titanate (PZT) - a ceramic material that is piezoelectric. Of all piezoelectric materials, PZT is the most efficient and is able to convert 80 per cent 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.