Magnetic field assisted high performance triboelectric nanogenerators based on P(VDF–HFP)/NiFe2O4 nanofiber composite.

Triboelectric nanogenerators (TENGs), which are powered by Maxwell's displacement current, have a wide range of applications, including energy harvesting and self-powered sensors. However, very little attention has been paid to the effect of the ferromagnetic medium on TENG displacement current. Herein, flexible ferrimagnetic poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF–HFP))/nickel ferrite (NiFe 2 O 4) fiber composite film based TENGs were fabricated and their performances were analysed. Highly crystalline, ferrimagnetic NiFe 2 O 4 nanofibers with high aspect ratio were prepared using electrospinning technique by systematic optimization of spinning parameters. Thereafter, the fibers were reinforced into the polymeric matrix to improve the β–phase and dielectric constant which in turn significantly enhanced the TENG performance. The β–phase enhancement in the composite films was confirmed by XRD and FTIR analysis; 77 % of the β–phase was achieved with the incorporation of NiFe 2 O 4 fiber. Morphological features were examined using SEM and AFM, which revealed more β–phase spherulite formation in the composite films. A notable increase in the dielectric properties was evidenced with the addition of NiFe 2 O 4 fibers and a maximum dielectric constant of∼26 was attained at 100 Hz. The TENG was developed using P(VDF-HFP)/NiFe 2 O 4 and nylon which generated an output voltage (V pp) and current (I pp) values of 584 V and 25 μA, respectively. Furthermore, the performance of TENG under an external magnetic field was examined, and a notable improvement in performance was observed, paving the way for the application of NiFe 2 O 4 fibers in hybrid energy harvesters and self-powered sensors. [ABSTRACT FROM AUTHOR]