In 2012, Zhong Lin Wang and his team, Georgia Institute of Technology, USA, developed a triboelectric nanogenerator (TENG) that converts mechanical energy into electricity. The miniature generator is based on the piezoelectric effect, which is electricity resulting from pressure, and the triboelectric effect, which is essentially static electricity.
The researchers paired two sheets of different materials together. One sheet donates electrons, and the other accepts them. When the sheets touch, electrons flow from one to the other. When the sheets are separated, a voltage develops between them. The output power density reaches 300 W/m2, volume density reaches 490 kW/m3, and a conversion efficiency of ca. 60 % has been demonstrated. The amount of charge transferred depends on surface properties.
The group has incorporated TENG into shoe insoles, whistles, foot pedals, floor mats, backpacks, and ocean buoys for a variety of potential applications. These gadgets harness the power of everyday motion like vibrations, rubbing, stepping, or ocean waves. So with one stomp of his foot, Wang, for example, can light up a sheet with a thousand LED bulbs.
The team is working on commercializing products to recharge cell phones and other mobile devices. Down the road, they envision these nanogenerators to be used to tap into the endless energy of ocean waves, rain drops, and wind.
- Presented at the 247th National Meeting & Exposition of the American Chemical Society (ACS), Dallas, TX, USA
- Video of the team’s work