A film that acts like a sponge is the key to picking up subtle movements that could power your device.
Ever wish there was something constructive that could come out of dropping or jostling your phone? Then you’re in for a treat. The newest advance in piezoelectric generators, which polarize crystals in a battery as a result of mechanical stress, has been developed by a group of researchers at University of Wisconsin, Sun Yat-sen University in China and the University of Minnesota Duluth, and it’s tiny enough to be embedded inside a cell phone or cell phone case. The results were published in the journal Advanced Energy Materials. According to a press release from the University of Wisconsin-Madison, it’s all about inserting interconnected pores of the correct size to get normally rigid materials to be as sensitive to vibrations as a sponge:
The nanogenerator takes advantage of a common piezoelectric polymer material called polyvinylidene fluoride, or PVDF. Piezoelectric materials can generate electricity from a mechanical force; conversely, they also can generate a mechanical strain from an applied electrical field.
Rather than relying on a strain or an electrical field, the researchers incorporated zinc oxide nanoparticles into a PVDF thin film to trigger formation of the piezoelectric phase that enables it to harvest vibration energy. Then, they etched the nanoparticles off the film; the resulting interconnected pores – called “mesopores” because of their size – cause the otherwise stiff material to behave somewhat like a sponge.
Previous incarnations of this technology have used generators embedded in sneakers or even backpacks, but this one is special in part because of its miniaturization and the fact that it doesn’t require any sort of cord to a device in order to work. The material’s thin film-like appearance makes it especially suited to mobile devices, what with their manufacturers’ fetishization of thinness. A component can also be attached to rough or curvy surfaces, such as human skin, in order to harvest power from the wearer’s motions. This makes for some enticing possibilities for integration with wearables. Maybe one day, exercise could really earn its keep in our everyday routine.
There’s no word yet on when such technology could become available, but we’re sure a crowdfunding campaign could win some supporters in record time.