Energy harvesting performance of magnetoelectric poly(vinylidene fluoride)/NiFe2O4 nanofiber films

Abstract

Abstract Flexible nanocomposite films of poly(vinylidene fluoride)(PVDF)/nickel ferrite (NiFe2O4) fiber were made using solvent casting method. The NiFe2O4 fibers with a diameter of 400 nm were synthesized initially by means of electrospinnig technique. Studies of XRD and FTIR confirmed the formation of both α and β phases in the composite films. The presence of α-phase was diminished with the incorporation of NiFe2O4 and a maximum β-phase percentage (68 %) was obtained. SEM and AFM analyses also demonstrated the transformation of the microstructures from α to β phase. The ferroelectric properties were tested with respect to NiFe2O4 loading and the composite film with 10 wt % NiFe2O4 exhibited a high Pmax value of 1.46 μC/cm2. VSM studies revealed the ferrimagnetic behaviour of the films and exhibited a maximum saturation magnetization value of 4.2 emu/cm3. Local ferroelectric properties were investigated through their domain switching behavior using dynamic contact electrostatic force microscopy (DC-EFM), and magnetic force microscopy (MFM) was used to analyze the magnetic properties. The magnetoelectric cross-coupling between ferroelectric and ferrimagnetic orderings is verified through the variations in ferroelectric parameters under different magnetic fields. Then a nanogenerator was fabricated using the composite films and generated an open circuit voltage of 10 V (peak-peak). Additionally, these films were made into magneto-mechano-electric (MME) generator, which could generate a 4.8 V (peak-peak) output voltage under a weak AC magnetic field of 10 Oe at 50 Hz.