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 P_max and U_charge of the composite film increased with increasing of the electric field. The P_max 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.