A new concept in energy harvesting could capture energy that is currently mostly wasted due to its characteristic low frequency and use it to power next-generation electronic devices. In a project funded by electronics giant Samsung, a team of Penn State materials scientists and electrical engineers has designed a mechanical energy transducer based on flexible organic ionic diodes that points toward a new direction in scalable energy harvesting of unused mechanical energy in the environment, including wind, ocean waves and human motion.
Devices to harvest ambient mechanical energy to convert to electricity are widely used to power wearable electronics, biomedical devices and the so-called Internet of Things (IoT) — everyday objects that wirelessly connect to the internet. 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.
“Our concept is to specifically design a way to turn low-frequency motion, such as human movement or ocean waves, into electricity,” said Qing Wang, professor of materials science and engineering, Penn State. “That’s why we came up with this organic polymer p-n junction device.”
Called an ionic diode, their device is composed of two nanocomposite electrodes with oppositely charged mobile ions separated by a polycarbonate membrane. The electrodes are a polymeric matrix filled with carbon nanotubes and infused with ionic liquids. The nanotubes enhance the conductivity and mechanical strength of the electrodes. When a mechanical force is applied, the ions diffuse across the membrane, creating a continuous direct current. At the same time, a built-in potential that opposes ion diffusion is established until equilibrium is reached. The complete cycle operates at a frequency of one-tenth Hertz, or once every 10 seconds.
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.
“Because the device is a polymer, it is both flexible and lightweight,” Wang said. “When incorporated into a next-generation smart phone, we hope to provide 40 percent of the energy required of the battery. With less demand on the battery, the safety issue should be resolved.”
According to the authors on the paper “Flexible Ionic Devices for Low-Frequency Mechanical Energy Harvesting” published online in the journal Advanced Energy Materials, “The peak power density of our device is in general larger than or comparable to those of piezoelectric generators operated at their most efficient frequencies.”
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 coauthors 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.
“Right now, at low frequencies, no other device can outperform this one. That’s why I think this concept is exciting,” Wang said.
Future work will involve further optimization and integration into smart phones and tablet devices.
Learn more: Capturing the Energy of Slow Motion
Receive an email update when we add a new ENERGY HARVESTING article.
The Latest on: Low-frequency mechanical energy harvesting
via Google News
The Latest on: Low-frequency mechanical energy harvesting
- Device harvests energy from low-frequency vibrationson August 31, 2018 at 7:27 am
A wearable energy-harvesting device could generate energy from the swing ... Collaborators at the University of Utah and in Penn State’s Department of Mechanical Engineering designed a novel ...
- Harvesting energy from low-frequency excitations through alternate contacts between water and two dielectric materialson December 6, 2017 at 4:00 pm
Here we report a method for directly harvesting ambient mechanical energy as electric potential energy through water droplets by making alternate contacts with CYTOP and PTFE thin films. Because CYTOP ...
- Harvesting Energy from Human Movementon July 25, 2017 at 9:17 am
A new, ultrathin energy harvesting ... from such low frequency motion has proven to be extremely challenging. For example, a number of research groups are developing energy harvesters based on ...
- New approach captures the energy of slow motionon December 20, 2016 at 4:00 pm
... of a paper published online in the journal Advanced Energy Materials ("Flexible Ionic Devices for Low-Frequency Mechanical Energy Harvesting"), "The peak power density of our device is in general ...
- Scalable energy harvesting of unused mechanical energy in the environmenton December 15, 2016 at 4:00 pm
A new concept in energy harvesting could capture energy that is currently mostly wasted due to its characteristic low frequency and use it ... toward a new direction in scalable energy harvesting of ...
- Capturing the energy of slow motionon December 14, 2016 at 4:00 pm
With less demand on the battery, the safety issue should be resolved." According to the authors on the paper "Flexible Ionic Devices for Low-Frequency Mechanical Energy Harvesting" published online in ...
- Power walk: Footsteps could charge mobile electronics (w/video)on February 11, 2016 at 7:39 am
An innovative energy harvesting and storage technology ... with a reasonably high frequency -- such as a mechanical source that's vibrating or rotating quickly. "Yet our environment is full of ...
- Your shoe may be able to harvest energy to charge your phoneon February 10, 2016 at 4:00 pm
Our phones seem to have a nasty habit of running out of juice when we’re running about, but soon, we may be able to ... energy source,” Krupenkin explained, “like a quickly vibrating or rotating motor ...
- Power walk: Footsteps could charge mobile electronicson February 9, 2016 at 4:00 pm
An innovative energy harvesting and storage technology developed by University ... "Yet our environment is full of low-frequency mechanical energy sources such as human and machine motion, and our ...
via Bing News