Effect of HNT@PANI hybrid nanoparticles on performance enhancement of electrospun PVDF nanofiber mat for flexible piezoelectric nanogenerators

Flexible PVDF-based piezoelectric nanogenerators (PENGs) are promising mechanical energy harvesters for powering wearable devices and portable electronics. In this work, a new hybrid nanocomposite was prepared by coating polyaniline on the surface of halloysite nanotube (HNT@PANI) and PENGs were fabricated by using electrospun nanocomposite fiber mats comprising HNT@PANI and poly(vinylidene fluoride) (PVDF). The rough surface of PANI outer layer and its electronegative properties favors a large interface and a strong interfacial interaction with PVDF matrix, which efficiently improves the β-phase crystal content and the crystallinity of PVDF simultaneously, resulting in an enhanced output performance in the fibrous nanocomposite PENGs. When the nanocomposite fiber mats are composed of 1 wt% HNT@PANI nanoparticles, the open-circuit voltage of the PENG is up to 30 V, which is six times higher than that of pure PVDF, and it can also light up 17 red LEDs. Furthermore, the open-circuit voltage was found unchanged after being subjected to continuous tapping for 5 weeks in the durability test. In addition, the PENG can charge a capacitor to 4.4 V within 60 s. This flexible self-powered PENG with good durability and high outputs has the potential to be used as a self-charging power source and applied in the field of wearable flexible electronic devices.