Nanogenerator uses vibrations to charge mobile phone

The so-called nanogenerator - created by engineers at the University of Wisconsin-Madison, the University of Minnesota Duluth, and China’s Sun Yat-sen University - is incorporated directly into the phone’s housing.

‘We believe this development could be a new solution for creating self-charged personal electronics,’ said Xudong Wang, an assistant professor of materials science and engineering at the University of Wisconsin-Madison.

Wang, his Ph.D. student Yanchao Mao and collaborators described their device - a mesoporous piezoelectric nanogenerator - in Advanced Energy Materials.

The nanogenerator takes advantage of polyvinylidene fluoride (PVDF), a common piezoelectric polymer material that can generate electricity from a mechanical force or generate a mechanical strain from an applied electrical field.

Rather than relying on a strain or an electrical field, the researchers incorporated zinc oxide nanoparticles into a PVDF thin film to trigger formation of the piezoelectric phase that enables it to harvest vibration energy. They then etched the nanoparticles off the film, with the resulting interconnected mesopores causing the otherwise stiff material to become sponge-like.