A team of researchers at the University of Illinois at Urbana-Champaign have developed a flexible piezoelectric implant that can harvest energy from natural motions within the body. The device has been tested on cows and sheep and has demonstrated that it can harvest enough energy from a beating heart to power a cardiac pacemaker.
The device is made of 500nm thick ribbons of lead zirconate titanate (PZT) surrounded by gold and platinum electrodes and then coated in a layer of polyimide to make it biocompatible. After performing numerous tests to find the current orientation, the voltage produced was approximately what they predicted theoretically and the implant did not interfere with the natural beating of the heart.