Instantaneous Piezoelectric Nanogenerator for Pacemaker Applications.

Implantable nanogenerators (NG) are a promising solution to the self-sustainable power source for cardiovascular implantable electronic devices (CIEDs), such as pacemakers, by harvesting biomechanical energy from heartbeats. Nevertheless, the conversion efficiency of mechanical energy into electrical energy has long been a significant challenge, limiting the practical application of NGs to effectively charge a power storage component. In this work, we report an instantaneous piezoelectric NG (i-PENG) design that converted the wave-like output of a regular PENG into output spikes with ~7 times higher amplitude. Due to the largely raised electrical energy, the i-PENG exhibited a substantially faster charging rate on a capacitor. The i-PENG was further integrated with a rectifier and a micro capacitor, serving as both the contact electrodes and an electrical regulating circuit. When implanted on a pig's heart surface, this integrated power system was able to charge a capacitance of 100 μF to 4 V in 13 minutes. This level of electrical power was able to operate a commercial pacemaker to provide regular stimulation signals. This study provides a design principle that can raise the electrical energy of the piezoelectricity, leading toward practical applications of PENG for powering implantable biomedical devices.