Gadgets could be powered by touch with energy harvesting

Gadgets could be powered by touch with energy harvesting
The energy used in operating touch devices could be harnessed to charge the gadgets being pressed thanks to a development at Penn State university. Researchers have demonstrated a new concept in energy harvesting in a project funded by Samsung.

The method captures energy that is currently wasted due to its low frequency using a mechanical energy transducer based on flexible, organic, ionic diodes.

Devices that harvest ambient mechanical energy and convert it into electricity are already used to power wearable electronics, biomedical devices and the IoT. 

The most common of these devices, based on the piezoelectric effect, operate most efficiently at high frequency, greater than 10 vibrations per second. But at lower frequencies their performance falls off dramatically.

Qing Wang, professor of materials science and engineering at Penn State, said: "Our concept is to specifically design a way to turn low-frequency motion, such as human movement or ocean waves, into electricity. That's why we came up with this organic polymer p-n junction device.

“Right now, at low frequencies, no other device can outperform this one. That's why I think this concept is exciting."

For smart phones, the mechanical energy involved in touching the screen could be converted into electricity that can be stored in the battery. Other human motion could provide the energy to power a tablet or wearable device.

Wang continued: "Because the device is a polymer, it is both flexible and lightweight. When incorporated into a next-generation smart phone, we hope to provide 40% of the energy required of the battery."

Future work will involve further optimization and integration into smart phones and tablet devices.

The research is detailed in "Flexible Ionic Devices for Low-Frequency Mechanical Energy Harvesting" published online in the journal Advanced Energy Materials.

Michael Hickner, associate professor of materials science and engineering, produced the ionic polymers, with Liang Zhu, a postdoctoral scholar in his group. Qiming Zhang, distinguished professor of electrical engineering, and his group focused on device integration and performance. Wang's group, including co-authors postdoctoral scholar Qi Li and graduate student Yong Zhang, focused on materials optimization. The co-lead authors are visiting scholar Ying Hou, recent Ph.D graduate Yue Zhou and visiting scholar Lu Yang, all part of Zhang's group.

Additional individual support was provided by China Scholar Council and the National Natural Science Foundation of China.

Source: Penn State