Piezoelectric fibers-based PVDF-ZnS-carbon nano onions as a flexible nanogenerator for energy harvesting and self-powered pressure sensing

Herein, an innovative piezoelectric nanogenerator (PENG) is fabricated by electrospun polyvinylidene fluoride (PVDF) and a hybrid nanofiller comprised of zinc sulfide nanorods (ZnS NRs) and carbon nano onion particles (CNOs). From a mechanistic point of view, it has been determined that ZnS nanorods contribute to the alignment of the electric dipoles in PVDF and enhance the overall piezoelectric properties of the composite nanofibers because of their intrinsic piezoelectric ability. CNOs as a family of carbon allotropes with electrical conductivity as well as easy preparation method from natural source of castor oil as a cost-effective preparation method can improve the piezoelectric performance of PVDF nanofibers by positively enhancing the charge transfer rate and thereby enabling the alignment of PVDF’s electric dipoles. The developed PVDF-ZnS-CNOs composite (with 0.15 wt% of CNOs loading) based PENG exhibited improved electrical functionality and stability. The maximum power density of approximately 30.15 μW/cm2, the load resistance of 1.0 MΩ, the open-circuit voltage of 14 V, and the short-circuit current of 35 μA were observed. In addition to evaluate the energy harvesting and sensing capabilities, the constructed PENG was utilized to identify numerous types of human movements, and several capacitors were charged. It was observed that a capacitor with a 1 µF capacity could be charged to 9.5 V under mechanical stimulation in 45 s, which shows a promising platform for eliminating the need for an external power source to operate portable gadgets. Consequently, the developed PENG possess high potential, which can be utilized as an alternative to conventional power supplies in self-powered devices by taking advantage of their flexibility and stability.