Arched material mesh concept for the triboelectric nanogenerator, aka TENG (via NANO Letters)
As we walk about in dry months desperately avoiding static shocks, we may soon encourage this effect. Zhong Lin Wang, the same professor of materials science working on the pyroelectric nanogenerators, has been leading a team working with piezoelectric nanogenerators. Unlike, the pyroelectric effect, which uses temperature fluctuations to harvest energy, the piezoelectric effect works by using mechanical motions to harvest and collect energy. The team has been hard at work for some time now trying to use the effect to create an efficient system. However, all of their previous experiments have yielded results that have not held any high hopes.
Nonetheless, the team has found that by combining static electricity with their previous system they have produced improved results. Using materials on the nanoscale, they create static electricity when moved against each other, just as a static charge builds on a balloon when rubbed against hair. The materials used within their system are a metal and polyethylene terephthalate, a plastic material. When these two materials come into contact, they create a charge which in return can produce a current when the films are flexed. By using nanotechnology and increasing the surface area of the materials, the team is hoping to increase the output produced by the device.
Although the technology is far from working, its way into our modern society it is still a step toward creating everpresent renewable energy sources. Shashank Priya, director of the Center for Energy Harvesting and Systems at Virginia Tech stated, “ I'm impressed with the power density here, other smart materials haven't produced enough power for practical applications.” The nanogenerator used can convert 10 to 15 percent of mechanical motion energy into electrical energy. By optimizing the geometry and taking advantage of nanotechnology, the team is hoping to convert up to 40 percent of the mechanical energy into electricity. Their next step is to demonstrate that it could work outside the lab. Wang envisions the device being used within an armband to collect energy.