Devices that harvest wasted biomechanical energy could make many new advances possible—including clothing that recharges personal electronics with body movements, or implants that tap the motion of blood or organs. Researchers at Georgia Tech have made the first nanowire-based nanogenerators that can harvest sufficient biomechanical energy to power small devices, including light-emitting diodes and a liquid-crystal display.

The generators take advantage of materials that exhibit a property called piezoelectricity. When a piezoelectric material is stressed, it can drive an electrical current. Piezoelectrics are already used in microphones, sensors, clocks, and other devices, but they aren’t very efficient for energy harvesting.

Zhong Lin Wang, who directs the Center for Nanostructure Characterization at Georgia Tech, has been working on another approach: embedding tiny piezoelectric nanowires in flexible materials. Wang has developed sophisticated nanowire generators and used them to harvest all sorts of biomechanical energy, including the movement of a running hamster.

Recently Wang’s team has developed a nanogenerator strip by adding several layers of zinc-oxide nanowires onto a thin metal electrode sitting on a sheet of plastic, and then covered the material with a polymer and topped it with an electrode. The resulting device is about 15mmx20mm, and it produces 2 volts (when compressed 4% every second), enough to drive a liquid-crystal display taken from a calculator.

New Electronics Product Design Ideas for Piezoelectric Nanogenerators:

  • Power shoes that can generate electric power while walking
  • PC/Laptop Keyboard that can generate electric power while typing with fingers
  • Power Keypad in portable electronic devices such as cell phones, which can generate electric power while using keypad
  • Power Carpet or door-mat, which can generate electric power when people walk on them