Researchers with Queen Mary University of London have teamed up with Nokia to build the first prototype smartphone that can be charged using only sound waves. QMUL's Dr. Joe Briscoe and Dr. Steve Dunn first came upon the idea last year when they noticed that playing music improved the performance of solar cells. From there, the team developed a nanogenerator capable of collecting energy from ambient sound. The key to the nanogenerator was zinc oxide, which can create voltage when it expands and contracts. Zinc oxide was formed into nanorods which could generate five volts of electricity, enough to charge a phone.
The team has already been able to cut costs of production for the nanogenerators, but the technology still needs time to mature and be built to scale. Ultimately though, it could mean that mobile devices of the future will be charged with the everyday sounds around you, like traffic, music, or even just talking. As the technology matures, it could extend battery life, or mean that you'll never have to plug in your phone again.