How is it possible to collect energy dissipated in the environment as a result of vibration, movement, walking and breathing?
Zhong Lin Wang, director of the Centre for Nanostructural Characterization at the Georgia Institute of Technology, put this question at the head of his research. Ten years ago, looking for an answer, Wang began using the piezoelectric method to convert mechanical energy into electricity. However, it was not applicable to all materials.
“Six months after the research started, my research team accidentally discovered the triboelectric effect,” Wang said. He noted that this effect can be used for a wide variety of materials (for example, for paper that can be wrinkled), while having a number of advantages:
• This technology is applicable at low amplitudes, which makes it possible to convert energy regardless of the intensity of body movements.
• It can be easily used for large-scale purposes: for example, you can create a spherical triboelectric generator to collect energy from the ocean surface around the clock, regardless of the depth of the water and the complexity of the underwater environment.“Surprisingly, the ocean can achieve 28 percent energy harvesting efficiency: a water surface that is one metre deep and the size of Georgia in square area can generate the equivalent of 10 % of the world’s energy consumption,” Wang said.
• The technology can be used for smaller tasks as well. An example is the Internet of Things: triboelectric generators can be used as stand-alone sensors that provide an electrical signal –they are suitable for medical devices and security systems.
Thanks to these advantages, triboelectric nanogenerators can find many applications. Wang said they can be used to:
• Charge a mobile phone or any other electrical device, including medical equipment (for example, a pacemaker) while walking.
• Keep your home safe: autonomous sensors can alert you when someone opens your door or walks on your carpet.
• Track the environment, whether it is monitoring water quality, air pollution levels, or the extent of forest fires.
Moreover, this technology can contribute to sensor technology in general. “However, my task was to work out the theory and create a basic technology that anyone can use as a foundation for some other purpose. Therefore, in the future, triboelectric nanogenerators will find applications that we have not even heard of so far,” Wang concluded.