Thin film, piezoelectric materials generate a small voltage whenever they are deformed, suggesting that they are suitable for tapping energy from freely available resources, such as the wind. Yet their low-energy production levels and lack of electrode durability have hampered development. NASA researchers have invented a system, method, and device for improving the performance and increasing the lifespan of small-form-factor, thin-film electrode, piezoelectric devices capable of interacting with the wind to provide power to wearable devices and stretchable electronics.
Two innovations were integrated into the device. First, polyvinylidene fluoride (PVDF) was combined with a metal oxide to improve conductance. Second, a new carbon electrode was designed to improve durability (compliance) and reduce susceptibility to fatigue while retaining flexibility. Additionally, to integrate the carbon nanotube components, a polymerto-polymer design was used that eliminates the need for adhesion layers.
A prototype device generated 1W power [at 15-mph (≈7 m/s) wind] with a single layer of PVDF [4×12 in. (≈10×30 cm) and 50 μm thick] sandwiched between two thin electrode films. A rectifier converts the AC signal into a DC signal, and stores the charge in a capacitor. This electric power can be used for low-power-consuming devices such as inaccessible sensors.