High performance piezoelectric nanogenerator by fiber microstructure engineering toward self-powered wireless sensing system

Piezoelectric nanogenerator (PENG) with these advantages of low cost, small volume and stable output in extreme environment is constantly required to develop self-powered sensing system in Internet of Things (IoT), which can relieve energy crisis and reduce labor maintenance costs. However, low electrical output of PENG severely restricts its application and has been a key challenge in the development of PENG. To attain high output performance, a new PENG based on core-shell heterostructure of barium titanate(BT)/polyvinylidene fluoride(PVDF) composite fibers coated with BT@Ag was designed for energy harvesting and wireless sensing application. The outputs of PENG with this special structure are enhanced near 3 times than that of PENG based on traditional fibers, benefiting from the enhanced induced-polarization and stress transfer mechanism in PENG, which is confirmed by experimental results and explained by multi-physics simulations. Moreover, the PENG can effectively harvest wind and acoustic energy, which can deliver the high outputs of 107.5 V and 16.18 µA under 12 m/s wind speed, 45.4 V and 6.5 µA under 110 dB sound pressure, respectively. To verify the practicability of the PENG, a whole self-powered wireless sensing system based on the PENG to harvest energy in environment was demonstrated, where the signal of humidity condition of soil can be sensed periodically and transmitted to mobile phone for further analysis. This work provides an effective strategy to boost performance of PENG and further paves a route about advanced self-powered wireless sensing technology in IoT.