PhD student Jun Liu has built a prototype of a triboelectric generator.
(Edmonton) Following their discovery of a new way to produce electrical power at the nano-scale, a University of Alberta research team has built a prototype of a device that turns mechanical energy such as a vibration into a stable electrical current.
"It's no longer a dream to be able to charge a battery or phone by simply walking around," said Jun Liu, a PhD student in the Department of Chemical and Materials Engineering. "This is something people will be interested in because it is relevant to daily life."
The prototype is based on a research conducted by Liu and his supervisor, chemical engineering professor Thomas Thundat, last year. They discovered a way to generate a high-density DC current using a sophisticated nano-scale microscope called an atomic force microscope. The devices uses a cantilever to "feel" objects too small to seen, in the same way a blind person uses a cane to gather information about the terrain around them. Liu found that the motion of the cantilever rubbing against a surface generated a direct-current with high current density.
The discovery set a new world standard in leading-edge devices called triboelectric nanogenerators.
Now, Liu has taken the device to a prototype stage, generating a steady current by manually rubbing a steel tip against silicon.
"We were able to generate DC electricity which can power up electronics easily and efficiently," he said of his new research. "We've just built a bridge between science in the lab with a real application. We've bridged the gap."
The technology can be used in any situation where an electrical charge is required. It could conceivably harvest the energy from the motion of your clothing while walking to charge personal electronics-or it might one day use the vibration of a beating heart to charge a pacemaker in heart patients.
The research findings appear in a high-impact research journal Nano Energy. Liu and Thundat have received a provisional patent on the technology.
The scientific phenomenon behind the technology is called tribo-tunneling, in which electrons that take shape while rubbing the silicon are able to "tunnel" through a one- to two-nanometre-thick oxide coating that naturally forms on silicon and acts as an electrical insulator.
"The oxide barrier doesn't allow anything to penetrate it but because it is so thin, when you rub on one surface and you're generating a lot of electrons, those electrons have a chance to tunnel from one side to the other by quantum tunneling," he said.
"We create charges and the charges tunnel through the oxide."
Liu says the next step is to build an advanced version of the prototype using microfabrication or 3-D printing technologies.