Vibration energy harvesting device based on air-spaced piezoelectric cantilevers

This letter reports a piezoelectric device based on air-spaced composite cantilevers for vibration energy harvesting. With air-spaced piezoelectric cantilevers, the voltage generated due to vibrations is larger since the distance between the piezoelectric layer and the neutral plane is increased. In addition, the energy conversion efficiency is also increased. A simplified analytical model was developed to explain the advantages and facilitate the selection of design parameters. Finite element simulation was also carried out to verify the analytical results. A prototype was successfully assembled and tested.