What if you could charge your portable device simply by having it move around in your pocket while you walk?
Texas A&M Professor Tahir Cagin believes that piezeoelectric materials, that convert motion into electric currents could be closer to applied applications thanks to their recent design breakthrough. (Not Image shown)
Professor Cagin and partners from the University of Houston are using piezoelectric material that can covert energy at a 100 percent increase when manufactured at a very small size – in this case, around 21 nanometers in thickness.
"When materials are brought down to the nanoscale dimension, their properties for some performance characteristics dramatically change," said Cagin who is a past recipient of the prestigious Feynman Prize in Nanotechnology. "One such example is with piezoelectric materials. We have demonstrated that when you go to a particular length scale – between 20 and 23 nanometers – you actually improve the energy-harvesting capacity by 100 percent.
"We're studying basic laws of nature such as physics and we're trying to apply that in terms of developing better engineering materials, better performing engineering materials. We're looking at chemical constitutions and physical compositions. And then we're looking at how to manipulate these structures so that we can improve the performance of these materials."
"Even the disturbances in the form of sound waves such as pressure waves in gases, liquids and solids may be harvested for powering nano- and micro devices of the future if these materials are processed and manufactured appropriately for this purpose," Cagin said.
Why is this important to the future?
Micro power systems are in high demand for portable gadgets and sensors like RFID tags used on products in 'smart supply chain' logistics. While batteries and micro fuel cells might be required for higher demand applications, piezeoelectric systems could find a role in the world of micro-power.
Researchers at Georgia Tech University have developed a new type of small-scale electric power generator able to produce alternating current (AC) through the repeated stretching and releasing of zinc oxide wires held with in a flexible plastic substrate that can be incorporated into almost any material.
This new type of piezoelectric generator can produce up to 45 millivolts by converting nearly seven percent of the mechanical energy applied directly to the zinc oxide wires into electricity. A complex array of these devices could be used to charge sensors or low power embedded MEMS devices.
Why is this important to the future?
Micro and nano-scale power systems are going to be in high demand in a future increasingly dependent on sensors and microelectronics. Piezoelectric generators could become a low cost, more durable alternative to miniaturized batteries and fuel cells used to power the billions of sensors, smart tags, and MEMS devices expected to hit the marketplace over the next two decades.
“The flexible charge pump offers yet another option for converting mechanical energy into electrical energy,” said Professor Zhong Lin Wang of the Center for Nanostructure Characterization at the Georgia Institute of Technology. “This adds to our family of very small-scale generators able to power devices used in medical sensing, environmental monitoring, defense technology and personal electronics.”
What to watch
Piezeoelectric materials convert mechanical changes into electrical current. As with everything else in the new energy sector, its future is being driven forward by materials scientists.
Earlier we featured breakthroughs at Texas A&M and also at Georgia Tech University on materials that generate small-scale electric currents when stretched or pressed.
There is talk of piezeoelectric iPods, but it is hard to imagine systems replacing batteries given the growth in electricity demand of portable gadgets. The best applications will likely be for sensors, microcontrollers, smart tags, and digital textiles that do not use high end processors.
Energy harvesting infrastructure?
Stories of energy harvesting dance floors have been circulating on energy and environmental blogs for months, but what about roads and railways that have more steady traffic?
Israel-based Innowattech claims to be the the first company to demonstrate industrial scale piezeoelectric solutions that 'harvest' energy from traffic moving over roads, railroads and airport runways. Their vision is to capture all the motion above ground into electricity for the local grid.
The obstacles to market are probably high given the demands of infrastructure and (very) conservative nature of structural engineers and regulators who build infrastructure for performance (not energy capture). Not to mention cost challenges in a down economy. But 'harvesting energy solutions' is a great meme and certaily has its role for future micro energy solutions. And who can argue the appeal of energy producing infrastructure and built environments?!
Related posts on The Energy Roadmap.com