Wireless power is the future of power, from wireless charging, like the Engerous wireless chargers that debut at CES 2018, to battery-free IoT Wireless Sensors. Now researchers are developing a method to wirelessly power everything with a new green energy source: triboelectricity.
Last year, a research team developed an ultra-simple triboelectric nanogenerator called U-TENG. This device is made of plastic and tape. It generates power from motion and vibrations through activities like hands clapping or tapping a foot. U-TENG detects the voltage through a wire, captures it and stores it in a capacitor and battery.
Since the development of U-TENG, researchers have developed a wireless version, called W-TENG. The development of a wireless version gives this technology a wide variety of applications.
W-TENG uses materials that are the complete opposite in affinity for electrons, which cause a voltage to be generated when they touch each other. In the development of W-TENG, the researchers replaced the plastic with graphene multipart fibers and a PLA biodegradable polymer. PLA separates positive and negative charges, and when paired with graphene it has the ability to conduct electricity. W-TENG uses Teflon as the electron grabbing material.
“We use Teflon because it has a lot of fluorine groups that are highly electronegative, whereas the graphene-PLA is highly electropositive. That's a good way to juxtapose and create high voltages," said Ramakrishna Podila, corresponding author of the study and an assistant professor of physics at Clemson.
The research used 3D printing and sonication to obtain the graphene needed for creating W-TENG. They used sonication to obtain the amount of graphene needed for W-TENG. They used a 3D printer to pull the fiber into electronics.
W-TENG generates up to 3000 volts of energy. This is enough power to run 25 standard electrical outlets, smart-tinted windows or an LCD monitor. W-TENG generates an electric field around itself that can be wirelessly sensed. This electrical energy can be stored in capacitors or batteries.
"It cannot only give you energy, but you can use the electric field also as an actuated remote. For example, you can tap the W-TENG and use its electric field as a 'button' to open your garage door, or you could activate a security system — all without a battery, passively and wirelessly," said Sai Sunil Mallineni, the first author of the study and a Ph.D. student in physics and astronomy.
W-TENG can be useful in areas that are limited in resources, like the ocean, space, and battlefield or even in underdeveloped countries.
The researchers are now focusing on getting a patent and starting to produce W-TENG for industrial applications. But before this happens, the team hopes to replace the Teflon with a more environmentally friendly material.
A paper on this research was published in Advanced Energy Materials.