Dielectric and Energy Storage Properties of BaTiO3/PVDF Composite Films Fabricated by a Spin-coating Process

Ceramic/polymer composites exhibit high dielectric constant, low dielectric loss, and high energy storage density. In this work, the characteristics of the spin-coating process to obtain a thin and uniform composite film without obvious defects were used to prepare composite films BaTiO3/PVDF. High-quality composite films enable better study of their macro- and microstructures, dielectric and energy storage properties. The results show that the BaTiO3/PVDF composite films prepared by the spin-coating process exhibit good uniformity in both macroscopic and microstructure. The average thickness is about 7 μm. At the same frequency, the dielectric constant increases with the increase in BaTiO3 content. The dielectric constant of 30 vol % PVDF composite film reached 62 at 100 Hz, which was nearly 6.8 times higher than that of pure PVDF. In addition, the dielectric loss of the composite film first decreased and then increased with the increase of frequency. With increasing of the BaTiO3 content, the breakdown strength of the composite film decreased. The Pmax and Ucharge of the composite film increased with increasing of the electric field. The Pmax of 30 vol % composite film was 4.41 μC/cm2 at 900 kV/cm. The energy storage density of 15 vol % composite film was 6.916 J/cm3 at 1500 kV/cm.