Electrostatic energy harvesting enhancement using variable equivalent permittivity

This Letter exposes an electrostatic-based vibration energy scavenging scheme using a two-layer configuration made of a high permittivity material and a low permittivity layer of variable thickness. Because of the significant change in the permittivity allowed by this process, the capacitance ratio variation is much larger than in the case of a single layer (whatever the permittivity of the latter), therefore allowing an increased efficiency and a significant energy gain, by a typical factor of 50. ► Variable permittivity increases conversion abilities of electrostatic devices. ► Variable permittivity can be easily obtained by adding a supplementary layer. ► It allows a gain of 54 in terms of scavenged power. ► For the same energy harvesting abilities, the size is reduced by 7400%.