Vibrations Could Power Self-Charging Devices, Researchers Say

Researchers have created a device called nanogenerator that can power an electronic device using vibrations.

According to researchers, the device can be used to charge phones by keeping them on a shaking surface such as the seat of a moving car.

Nanogenerator could be directly incorporated into the electronic device, researchers said.

"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, one of the study authors, according to a news release.

Several research groups and tech companies are trying to develop self-charging electronic devices. Yang Yang et al., showed in 2011 that it is possible to use photovoltaic filters to power phone displays. Nokia incorporated a pad for wireless charging to the Lumia 920.  In 2012, an Apple patent hinted at a new idea for self-charging smartphones.

The latest study on the, "mesoporous piezoelectric nanogenerator," is published in the journal Advanced Energy Materials.

The device works common piezoelectric polymer material called polyvinylidene fluoride, or PVDF. Piezoelectric materials can convert electricity from mechanical force or vice versa.

The idea of using piezoelectric materials to charge phones has been thrown around for quite some time now. MicroGen Systems (Microgen) - a tech company from Ithaca, had earlier described building a device that generates electricity using ambient vibrations.

Georgia Institute of Technology researchers too showed that PVDF can be used to covert mechanical strain into chemical energy.

In the present study, researchers embedded zinc oxide nanoparticle into a thin film of PVDF. The formation helped researchers develop a piezoelectric phase that could harvest vibration energy.

Researchers then etched the nanoparticles off the film, which made the film look porous. These pores called 'mesopores' made the film sponge-like.

According to the team, this sponge-like structure is the key for the vibration energy. "The softer the material, the more sensitive it is to small vibrations," said Wang.

The nanogenerator has this mesoporous film between two sheets of electrodes. The thin device can be attached to any surface, including human skin.

"We can create tunable mechanical properties in the film," he said. "And also important is the design of the device. Because we can realize this structure, phone-powering cases or self-powered sensor systems might become possible."