Written by: B.C.
Have you ever had your phone battery mess up or you’ve lost your charger? Some day soon that might not be a problem. Four years ago Korean scientists attempted to charge a phone with only sound. They weren’t succesful, but with new technology and a colaborative effort between the phone company Nokia and Queen Mary University of London (QMUL) have succeeded.
The way they were able to do this is with a piezoelectric effect. For example, you could charge your by ambient sound, such as cheers from a football field or chatter from a coffee shop. What they did was use zinc oxide nanowires to convert vibrations caused by sound into electricity. The researchers used zinc oxide in the form of a sheet of tiny nanorods. These nanorods bend in response to sound waves which creates mechanical stress and zinc oxide will produce electrical current when exposed to mechanical stress.
The scientists started their test by spraying liquid zinc oxide onto a plastic sheet. The sheet was placed in a mixture of other chemicals and then heared up to 90ºC (194ºF). After being heated up the zinc oxide grew into an array of nanorods. The scientists harvested the volts they generated by sandwiching the nanorod sheet between two electrical contact sheets. These contract sheets would usually be made of gold but the scientists found a way to use ordinary aluminum foil instead.
The prototype energy-harvesting device the scientists came up with was about the size of a Nokia Lumia 925. The device was capable of generating up to five volts using everyday background noise from things like traffic, music, and voices. Five volts is enough to charge a moblie phone, and is much higher than the 50 millivolts that the korean scientist came up with four years ago. QMUL’s Dr. Joe Briscoe says “Being able to keep mobile devices working for longer, or do away with batteries completely by tapping into the stray energy that is all around us is an exciting concept. We hope that we have brought this technology closer to viability.” If this new technology goes mainstream the whole way we use batterypowered machines may be changed forever!