Tribo-electricity has been out in the news for quite some time with scientists finding ways to harvest this energy efficiently. Now researchers at the Georgia Institute of Technology say they have built a simple prototype device that converts stop-start movement into power.
The prototype utilizes a breakthrough radial-arrayed rotary electrification process that harnesses power in a reliable, free and efficient as well as cost effective manner.
Zhong Lin Wang, a professor of materials science and engineering, said that waves, walking and dancing – even rainfall, computer keys or urban traffic – could one day be harnessed to drive sensors, mobile gadgets or even electricity plants. “Our technology can be used for large-scale energy harvesting, so that the energy we have wasted for centuries will be useful,” he intoned.
Tribo-electricity has so far been considered unpredictable, with it being shunned as a power source. The preferred method has been magnetic induction – a turbine driven by nuclear- or fossil-powered steam or water that is plagued by its own demerits.
Wang’s team said they had overcome key hurdles to converting a haphazardly-generated electrical charge into current, with the same being published in the journal Nature Communications
Their prototype comprises a disc about 10 centimeters (four inches) across, designed to show the potential from a small, portable generator moved by ambient energy. Inside are two circular sheets of material, one an electron “donor” and the other an electron “receiver,” brought together through rotary movement.
If the sheets are separated, one then holds an electrical charge isolated by the gap between them. Sandwiched between the two discs is a third disc with electrodes, which bridges the gap and helps a small current to flow. At a top speed of 3,000 revolutions per minute, the device generated 1.5 watts.
This gave it an energy efficiency of 24 percent, three times greater than piezoelectric, the previously best source of mechanical electricity harvesting – and as efficient as magnetic-induction turbines.
It can run on a gentle wind or tap water, or “random jerky motions,” including human movement, to provide the rotation, Wang said. “As long as there is mechanical action, there is power that can be generated.”
The prototype used copper for the rotator and gold for the electrodes in lab tests, but these could easily be substituted for low-cost synthetics, he said. The team is working on ways to scale up tribo-electric energy for harvesting power from the ocean.
The triboelectric generator can effectively harness various ambient motions, including light wind, tap water flow and normal body movement. Through a power management circuit, a triboelectric-generator-based power-supplying system can provide a constant direct-current source for sustainably driving and charging commercial electronics, immediately demonstrating the feasibility of the triboelectric generator as a practical power source.
Given exceptional power density, extremely low cost and unique applicability resulting from distinctive mechanism and structure, the triboelectric generator can be applied not only to self-powered electronics but also possibly to power generation at a large scale.