Flexible and ferroelectric electrospun PVDF- non-stoichiometric PZT nanogenerators (PENGs) membranes for low-frequency acoustic energy harvesting

Abstract

Listen

Translate article

Acoustic energy harvesting (AEH) at low-frequency has been exposed to serious problems such as low energy of input sound and lack of efficient materials to absorb the sound and convert it to electrical power. This study focused on the enhancement of the AEH performance of polyvinylidene fluoride (PVDF) membrane via the incorporation of non-stoichiometric PZT (nsPZT) nanoneedles as piezoelectric nanogenerators (PENG). The nanofibrous membranes with different amounts of PENG (x = 0, 2.5, 5, and 10 wt %) were synthesized by the electrospinning method. The nsPZT was provided via Nd3+ and Nb5+ co-doping as a novel approach. The microstructures revealed that the PENG was embedded well inside the fibers (x = 2.5), while the agglomerates were formed at higher amounts (x = 10). Also, the fiber diameters and porosity of membranes were changed. It was found that the maximum crystallization of the β-phase of PVDF has occurred at x = 2.5 (71 %). The dielectric of the PVDF membrane decreased with increasing the x factor due to the formation of further pores. In contrast, the ferromagnetic properties, piezoelectric sensitivity, and electrical conductivity were improved by adding the PENG. The maximum coercivity of 750 Oe, piezoelectric sensitivity of 1.959 V N−1, and minimum sheet resistance of 1.2 kΩ.sq−1 were achieved by x = 2.5. The noise reduction coefficient (NRC) of the PVDF membrane was enhanced drastically (53–163 %) by adding the PENG. The AEH performance was also enhanced by adding the PENG. The highest power density was achieved 0.0822 W g−1 (56.23 W m−2) by the PVDF-PENG membrane (x = 2.5) under 90 dB sound pressure at 2000 Hz frequency. These findings suggest the high potential of nanofibrous PVDF-PENG membrane for use in low-frequency AEH systems.