Improving Polarization Hysteresis to Enhance Dielectric and Energy Storage Performance of Polyvinylidene Difluoride-Based Nanocomposite Films

As a ferroelectric polymer with excellent performance, polyvinylidene difluoride (PVDF) has an irreplaceable position in film capacitors. However, the problem of polarization hysteresis needs to be effectively improved. Consequently, linear polymer polymethyl methacrylate (PMMA) was introduced into the PVDF blend, and PMMA could inhibit the polarization behavior of PVDF in the amorphous region, thus weakening the local polarization field and reducing the coherent coupling between ferroelectric domains. In addition, high dielectric constant barium titanate (BaTiO 3 ) nanoparticles were introduced to enhance the depolarization field inside the crystalline phase, and the synergistic effect of PMMA and BaTiO 3 improved the polarization hysteresis and dielectric properties of PVDF. Preparation of PVDF/PMMA/BaTiO 3 films was undertaken through the utilization of a spin-coating process, and the film thicknesses were uniform without obvious aggregation. The maximum discharge energy density of the 30 wt.% BaTiO 3 nanocomposite film was 1.87 J/cm 3 , and the dielectric loss (tanδ) can be stabilized at 0.12 and below. At 100 Hz, the E b and tanδ of the 30 wt.% BaTiO 3 nanocomposite film were 1400 kV/cm and 0.12, respectively. The favorable performance of the films has also been displayed by the phase field simulation results.